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Linux® Troubleshooting Bible

1. e 110 Backup Strategies ee 112 WhattoBackUp 4 2 koe poe Gow mox edm A E eee dom ed 112 Backing Up the Entire Operating System 113 Other Important System Config Files 114 Backing Up Databases 22e 115 Setting Up Tape Drive Devices o ln 116 Shutting Off Services iii Re a da 117 Backup Tools and Howto Use Them 118 Taror Star ia Sed xe a a a 119 DUMp RESTOTE ica A A an a e A Oe Be OR 119 Amanda Client Server 2 0 2 222r 120 Other Useful T ols pe e beo REG ie acl no be ee EUR 121 Backup Examples 222A 122 Using Tar Locally 25 oe mum ee Ba ae Se as a 122 Scripting Tar with Runlevel4 lll 122 Using Tar Remotely o a 124 Using Dump ci a Ee ete CE 125 Using Dump Remotely eer 129 Testing and Doing Restores 0 es 129 Restoring from Tar ee 130 Restoring from Dump ere 130 Restoring MySQL Databases lees 132 Server Migrations 1 62 GL om v a da a eee 133 Disk to Disk Magic lr 133 SoftwarelIss es X sa od di A sivi 133 Web ApacheGotchas e 135 SECUELA dort d e Bee eR 135 Backup Related Resources 222A 136 Summary PET TTTT 136 Part III Troubleshooting Basic Features 137 Chapter 6 Troubleshooting Tools lt lt lt lt 139 Getting Around with the S
2. 173 Configuring the Mouse after Installation 173 Digging into the X Server and XF86Config File 174 Understanding the X Server 2 2222s 174 Understanding the XF86Config File o o 175 Setting and Tuning Your Video Driver llle 179 Determining Your Video Card Driver o a 180 Tuning and Testing Your Video Card o 182 Refining Video Settings with xvidtune a 184 Video Troubleshooting Tips ls 185 Tips for Getting DRI to Work o eee 186 Tips for Particular Video Cards Chipsets 186 Tips to Fix Video Crashes 188 Mouse Troubleshooting Tips e e 188 Video Troubleshooting Reference eee eee 189 SUMMARY 3 5 oho BO nd hd At A Ge Serta Gh ares foe er Gace eni id Ta 190 Chapter 8 Software Package Troubleshooting 191 Introduction to RPM sek A AAA AA 191 Installing Upgrading and Deleting Packages 192 Checking Software Packages o o e 193 Checking Software Package Signatures 194 Checking Software Package Dependencies 197 Cross Checking Software Package Contents 200 Checking Software Package Scripts 2 0004 201 Querying Software Packages ee
3. 73 Identifying Your Enterprise Server Needs o 74 Locking Down Your Template Installs 74 The Final 6postscript ocaci n 80 Creating a Kickstart Provisioning Server o 82 Centralizing and Standardizing Your Kickstart Files 83 Creating Your Kickstart Provisioning Boot Media 85 Finding Red Hat Boot Images 02 0000 ee eee 85 Considering Network Install Options lle 87 Creating Customized Boot FloppieS o 88 Making a Network Install BootCD o o 90 More Floppy and CD Customization Information 94 Testing Your New Kickstart Media o a 94 Floppy Installs 0 2 di Britt Be ee eh A eS 94 CDInstall 23e ike ble A e a ha aad 95 Troubleshooting Common Kickstart Problems o 96 Kickstart Troubleshooting References ees 98 SUMMA Ys i23 208 AS A ed EN ot nC APR STE Se HE IE NALE S 98 Chapter 5 Preparing for Backups and Migration 99 Backup Types lt A AW eau See SE DS 99 TypesofBackups 4 3 3 kg RR Ae RU EUR RUE eene 100 Contents XIX Which Backup Strategy Should You Use 0 o 103 The Classic Elegance of Level Based Backups 103 The Power f TOIT ice as X eee ts da 104 Backup Media Types and Hardware o 106 Other Backup Hardware Tips
4. Core installation Once you have made your selection click Next to continue C3 Hide bolo 9 Release Naes Back gt Next Figure 2 3 Fedora detects an earlier Fedora or Red Hat Linux installation and gives you the option of upgrading If installation failed at some point go through the sections on choosing hardware and troubleshooting installation problems to help track down and solve the problem Choosing Hardware By using computer hardware that is both supported and contains the recommended amount of power RAM CPU and so forth you have the best chance of successfully installing a Red Hat Linux system This section presents some of the issues related to making sure you have computer hardware that will work for Fedora and Red Hat Linux systems Random Access Memory RAM Having enough RAM installed on your computer is critical to a successful installation of Fedora or Red Hat Linux Recommended memory amounts for Fedora Core are as follows Text mode 64MB minimum Graphical mode 192MB mimimum Graphical mode 256MB recommended 24 Part Getting Going Note Note If you are running in graphical mode with less than 192MB you will almost certainly be unhappy with performance at some point To run a Red Hat Linux system on less than 64MB of RAM you might consider looking into the RULE project www rule project org RULE Run Up2date Linux Everywhere is a version
5. iue eR REG hoe eR des mde ue Pes 269 Full Firewall or Trusted Access Control o 270 xxii Contents Linux Firewall Mechanisms e 272 TCP Wrappers usen dva ap AA POS Row ed 9X ovx 273 iptables a seansi g w asta sa o ar di a Xu 274 TCP Wrappers Securing Local Services o o 275 The host access Files ee 277 TCP Wrappers Troubleshooting Tips o 280 iptables and the Single Server e e 281 iptables Configuration Tools o eee 282 Configuring a Stand Alone Server lees 283 Hands on Testing with iptables Rules 288 iptables and Network Firewalls o o eee ee 293 Building Firewall Rules o pee ee ee ee 295 Apply Security Settings les 298 The Final Configuration een 300 Graphical Firewall Tools ee 302 Firewall Distributions o lee 302 Firewall Tools 2 wee gig 2 Ros a a teu ng 302 Troubleshooting iptables 0 00 eee eee eee eee 304 Enabling Packet Forwarding ees 304 SSH Access Denied lee 304 Conflict withipchains 2e 305 Denied Access PersistS 24 oi o Ro EA SG PERSE 306 Firewall RESQUECES 2 2 pod rs S Ge E SUE eee oe WP A S RS 307 SUMMA A PIERDE 309 Chapter 12 Troubleshooting BIND9 and DNS 311 DNS History and Theor
6. serial or scrial mouse Hint If the Cordless Optical Mcuse USD connector your mouse plugs MouseMan FirstMoLse PS 2 into is round itis a PS 2 ora MouseMan F rstMouse PS 2 Bus mouse if rectangular it is a USB mouse if trapezoidal it is a serial mouse MouseMan FIrsiMoLse serlal MouseMan F rstMouse serial b Microsof b MM Mouse Systems Mouse se al Try to find an exact match If an exact match cannot be found choose one which is No mouse l compatible with yours Devica Otherwise choose the 4 Z A 50 COMI under DOS appropriate Generic mouse i S1 COM2 under DOS ype COM3 under DOS Ifyou have a serial mouse pick 3 COMA under DOS the device and port itis fs O Emulate 3 butions G3 Hide bio 9 Release Nores Back p Next Figure 2 1 When configuring a mouse during installation select the manufacturer and model number when possible Install type Fedora offers special software package groups and configuration settings for Personal Desktop Workstation and Server installs Advanced users typically choose Custom install where they can install everything a minimum set of packages or any combination of packages they choose Advanced users who repeat the same install process multiple times can use the kickstart feature described in Chapter 4 Disk partitioning The Disk Druid screen lets you add modify or de
7. 202 Querying Local or Remote Packages s 203 Querying Individual Packages lees 203 Querying Multiple Packages 2 lees 205 Verifying Software Packages 22e 206 Repairing a Broken RPM Database o 00000 ee 207 Troubleshooting Software Package Tips o 207 Software Package Troubleshooting Reference 208 Summary uox erede REGE X Cy anis a vg y I due ER OS 209 Chapter 9 File System Disk and Power Troubleshooting 211 Starting with Linux File Systems 2e 211 Contents XXI Checking Partitions and File Systems o a 212 Troubleshooting Partitions and FileSystems 215 Checking and Tuning Your Hard Disk o e 0004 221 Getting Information about Your Disk 221 Changing Hard Disk Settings o 224 Making hdparm Changes Permanent o a 232 Managing Power Settings for Laptops o llle 232 Managing Power with APM e e e 233 Managing Power with ACPI eee 235 Changing Power Settings with hdparm 235 Disk File System and Power Troubleshooting References 236 DUMMALY A eo ge ut p tte M tp RE NA 237 Part IV Troubleshooting the Network 239 Chapter 10 Detecting and Responding to Intrusions Ca xu ra ES 241 Intrusion Detection and Response An O
8. 342 Using PCL Modenms ous RIEGO SEU wee ee ge EORR S 342 Using USB Modems eh 346 Using Serial Modems e 347 Probing and Trying Your Modem s 347 Setting Up Your Modem through the GUI o 349 Setting Up Your Modem with minicom 350 Starting minicom p st a ec meubu y i e ee y 351 Displaying and Changing Modem Settings 352 Making Modem Settings Permanent 354 Modem Troubleshooting Tips aaa s 354 Finding Modem Troubleshooting Resources 355 S mmafy hoa a deese MUN E AED O ng a Ge RE 356 Part V Troubleshooting Internal Services Chapter 14 Printer Troubleshooting 359 CUPS The Common UNIX Printing System lll 359 Getting the Right Printer e ee ee ee 362 Understanding Page Description Languages 362 Finding Details on Print Drivers o 363 Where to Get Help Choosing a Printer 363 Setting Up a Printer under Fedora Core o 364 Setting Up a Printer during Installation o 364 Using Red Hat s Printer Configuration Tool 365 Adding a Printer Using the CUPS Web Configuration Tool 368 Sharing a Printer under Fedora Core 00000004 371 Going Beyond Setup 2 373 Troublesh
9. Part IV Troubleshooting the Network 239 Chapter 10 Detecting and Responding to Intrusions 241 Chapter 11 Firewall Troubleshooting ellen 265 Chapter 12 Troubleshooting BIND9 and DNS o o e 311 Chapter 13 Modem Troubleshooting 0 0 0000 eee ee ee ee 341 Part V Troubleshooting Internal Services 357 Chapter 14 Printer Troubleshooting 0 0 0 0 0000000 359 Chapter 15 Samba Troubleshooting en 385 Chapter 16 NFS Troubleshooting eh 407 Part VI Troubleshooting External Services 425 Chapter 17 Web Server Troubleshooting o e lees 427 Chapter 18 File Transfer Troubleshooting llle 455 Chapter 19 E Mail Server Troubleshooting a 485 Appendix A Fedora Software Repositories Appendix B Troubleshooting SUSE Linux e 523 Appendix C Troubleshooting Debian GNU Linux Contents Preface cana dd aos vii Acknowledgments i oranes RE Reo A Qe S TR RC d xii Part I Getting Going 1 Chapter 1 Introduction to Linux Troubleshooting 3 Introducing Fedora Linux e 4 Learning Linux Troubleshooting with Fedora 4 Finding Opportunities with Fedora llle 5 Going with Fedora Without Going It Alone llle 9 Choosing a Fedora Version eee eee
10. a boot server to let the client boot the necessary install image PXE install images are contained on CD 1 for Fedora and Red Hat Linux systems in the images pxeboot directory Then set up an install server as described in Red Hat Linux Bible If PXE support is built into the network interface card on the machine you want to install from you can enable PXE in that computer s BIOS When you boot the computer select to boot from PXE When prompted identify the install method you want to use and continue as you would with any network install There is a white paper from HP on doing a PXE install You can find it here http h18000 wwwl hp com products servers linux redhat whitepapers html The Linux on an IBM ThinkPad page www solarblue net docs x31 htm provides a good description of how to do a PXE install including how to set up the PXE boot server Note Chapter 2 Troubleshooting Installation 29 No CD drive lf there is no CD drive on the computer you can install from any of several other media types By first creating a floppy boot disk as mentioned in the previous point you can install from software that is located on an HTTP FTP or NFS server An ethernet card is required for each of those network install types If you can get copies on to the hard disk you can install from that medium as well Checking media The media could be so bad that you may not even get to a boot prompt To find out if the medium is truly
11. administration utilities had their names changed to system config So anywhere in the book that we discuss the commands that launch graphical administration tools you should change redhat to system when you type the command The XFree86 X server used in Fedora Core 1 has been replaced by a new X server from X org During descriptions of troubleshooting video in Chapter 7 you may find differences in how some of the X related commands behave Likewise in the course of normal improvements to Linux software such as new versions of KDE and GNOME desktops in Fedora Core 2 some of the steps and options described in this book which was based on Fedora Core 1 may differ Getting Fedora You need Fedora Core Linux operating system to use this book When Red Hat Inc transitioned its operating system from Red Hat Linux to Fedora it stopped producing boxed sets of that product To follow along with this book you should get the three CD Fedora Core 1 set in one of the following ways 4 Red Hat Linux Bible Fedora and Enterprise Edition The complete three CD installation set for Fedora Core 1 comes with this edition of Red Hat Linux Bible If you are new to Red Hat Linux Fedora or Linux in general Red Hat Linux Bible covers the basics you need to use administer and set up servers for Fedora Core Linux Troubleshooting Bible builds on those basics Downloading You can download the ISO images of the CDs from the Fedora Project webs
12. boot prompt at the bottom In most cases you will choose from one of the following two installation types Graphical installation lf you just press Enter or wait a few seconds for it to start automatically Fedora Core 1 will start up the graphical installation process and expect to install the software from the three CD set This is the default way to install Red Hat Linux systems Text based install lf you have a low memory computer unsupported graphics card or simply don t feel the need for colors and icons you can do a text based install To start a text based install type linux text from the boot prompt Starting the installation process essentially means booting a small Linux kernel that in turn runs the Anaconda installer Because you are starting an install process there are several different install related options you can add to direct how the installation process should behave Likewise you can also pass options to the kernel that can specifically tell the kernel about how to deal with your hardware especially if the installation process is unable to properly detect your hardware 30 Part Getting Going Note Trying Red Hat Installation Options The following points describe different problems that can arise during installation and that you might be able to correct by trying different options from the installation boot prompt 4 Corrupted CDs Before you install Fedora Core or Red Hat Linux from CD
13. damaged beyond repair try inserting the first boot CD into any running computer Linux or Windows and try to browse the contents of the CD If you can access the CD and some of the files on that CD chances are that you should be able to boot the CD The CD could still be corrupted but you can find that out with a media check when you boot the install process Screen is unreadable My first suggestion to installing on a machine where the GUI is unreadable is to run the installation in text mode boot linux text Some experienced system administrators prefer text based installs because it allows them to deal with their video cards after the operating system is installed Instead of having the system boot to runlevel 5 with a GUI that may or may not work the computer will boot runlevel 3 text login prompt and let the administrator get the GUI going on a working system always do a text based install when I have an NVIDIA based card since know I m going to replace the video driver after installation with an NVIDIA proprietary driver If you are having trouble with the screen not being readable in text mode there are some ways Of telling the install process something about your graphical hardware See the description of the vga option earlier in this chapter for further information From the Boot Prompt If you are able to successfully boot the Fedora Core or Red Hat Linux CD you should see the installation boot screen with a
14. disappearing for Red Hat Linux and Red Hat s free Fedora Project offered with no long term official Red Hat support some people continuing to use free Linux distributions are feeling left out in the cold If you are devoted to the idea of using free Linux distributions that don t have commercial support options you have another option learn to troubleshoot Linux yourself Getting in Deeper Troubleshooting is an often neglected area of system administration After books and manuals have gone through the steps to configure and use a feature usually they ve filled up their chapter and are on to the next topic So what happens if you get to the end of a setup procedure and the feature doesn t work Linux Troubleshooting Bible was created to help you troubleshoot failures that you may encounter as you use Linux For most features covered in Linux Troubleshooting Bible we take you through some quick basic steps of setting up that feature In many cases running the basic setup will uncover some step you forgot to do For more details on basic uses of the feature we point you to books such as the latest edition of Red Hat Fedora Linux Bible mailing lists and websites After you have done what should have worked and found that it didn t work we tell you how to go a bit deeper For example nearly every type of Linux service outputs messages to log files Daemon processes have verbose or debug modes to spew out reams of messages for
15. of Red Hat Linux that was modified to run on less powerful computers According to the RULE project speaking on an earlier version Red Hat Linux will abso lutely not install with less than 20MB of RAM Using RULE the project claims that you can install on a Pentium 200 MHz with 12MB of RAM in about 1 hour So if you are trying to install on low end hardware RULE might be the way to go If you meet or exceed the minimum RAM requirement in most cases the Anaconda installer will detect it So the installation should just work without any special consideration of RAM However there are some cases where the kernel cannot detect the actual amount of RAM In these cases you can run a memory test to find out how much RAM you actually have as explained in the next section then provide an option when you boot the install process to tell the kernel how much memory to use Testing Memory from Installation Boot Prompt To run a memory test boot from the first installation CD Fedora or Red Hat Linux Then type the following at the boot prompt boot memtest86 The memtest86 feature runs the memtest86 stand alone memory diagnostic utility Besides accurately reporting the total amount of available memory memtest86 also tests for memory failures level 1 and level2 cache memory and reserved memory It also reports on the memory chipset and method used to find memory size e820 by default For more information on memtest86 refer to www memte
16. or software fix available to overcome the problem If you can t find the exact bug you encountered in the database you might also want to check a Fedora mailing list on the topic to see if the problem has been encountered before you file a bug report To search Bugzilla go to the Red Hat Bugzilla site http bugzilla redhat com bugzilla and enter a search term Report lf you feel that the bug has not been reported yet you can enter a Bugzilla report into the database When you do make sure that you have as many details available about the problem as possible before you enter the report To enter a bug report you need to give a valid e mail address and password To get an account or just log in to enter a bug report go to the following web address http bugzilla redhat com bugzilla enter bug cgi 16 Part Getting Going Note Once you log in check the frequently reported bug list and check the latest errata updates to see if your bug has already been dealt with Then select Fedora Core to enter a new bug report by selecting the component software package severity platform priority summary description and other information about the bug If you have never entered a bug report before click the bug writing guidelines link from the Enter New Bug page Those guidelines will give you good advice on how to pass on the most important information about your bug to help the developers reproduce and fix the problem
17. prompt The modes you enter determine if the install is run in text or graphical mode if installation is done interactively or from a kickstart file and whether the software is installed from the CD network server NFS HTTP or FTP to name a few choices You can choose the modes Anaconda can run in to suit your situation For example installation normally runs in graphical mode but you can run it in text mode to skip over any problems you might have with a video card You can also add kernel options from the installation boot prompt This can help you overcome some of the most common factors related to installation failures which are due to unsupported improperly probed or buggy computer hardware Books such as Red Hat Linux Bible and the installation manuals that come with Fedora or Red Hat Linux do a good job of taking you through the steps to install Red Hat Linux distribution Because our aim here is to help you troubleshoot the following list is just to remind you of the choices you ll face during Fedora or Red Hat Linux installation Check media You are given the option to verify the integrity of each of the CDs in your installation set before starting installation Language You need to choose which language to use during installation You can add other languages later Keyboard Different languages and countries use different keyboards Choosing the wrong keyboard type can result in letters not being where you expect
18. sitting down to use this book with Fedora Core 2 you should be aware of several differences from Fedora Core 1 Here are some of the major ones 4 Linux 2 6 5 kernel The Linux 2 6 kernel is a major upgrade from the 2 4 22 kernel included in Fedora Core 1 New features should result in improved performance more supported hardware and better scalability For the most part the new kernel shouldn t change how you use this book However visible reflections of the new kernel include a new sys file system where you can view and change kernel information and device files represented by ko instead of o suffixes Advanced Linux Sound Architecture ALSA The underlying mechanism for sound in Fedora Core 2 is ALSA replacing the Open Source Sound system OSS used in Fedora Core 1 and earlier Red Hat Linux distributions system config tools To give a more generic feel commands to launch graphical administration tools that previously began with redhat config now begin with system config For example the redhat config network command is now system config network Anytime you encounter a command beginning with redhat config try system config in Fedora Core 2 instead 4 Security Enhanced Linux The SE Linux feature pervades many aspects of the Fedora Core 2 operating system This new security model can be used to overcome the monolithic root owns the world approach to security in earlier Linux and UNIX systems Using access contro
19. that s okay since most Debian users prefer to read man pages anyway Appendix C covers Debian troubleshooting issues that will help you understand what you will face if you want to transition your Fedora and Red Hat Linux troubleshooting skills to Debian Using Linux Troubleshooting Bible Our primary goal with Linux Troubleshooting Bible is to give you the resources you need to overcome any problems you might have using and administering Fedora Linux primarily as well as other Red Hat Linux systems We take two approaches to attaining this goal Teaching you how to troubleshoot Fedora on your own Getting you in touch with other Fedora resources By focusing mostly on command line tools and text based configuration files you ll learn basic troubleshooting techniques that will apply to most Linux distributions For example whether you use an Apache web server from Fedora RHEL SUSE or another Linux distribution the httpd conf file will still be the basic file you will troubleshoot if something goes wrong with your web server For the features we cover we try to give you multiple commands and options to try out Because we know we can t cover every issue that might come up for most subjects we will point you to mailing lists FAQs or other online resources you can turn to for more information Approaching Linux troubleshooting You can use this book as a reference check it when you have a problem or a guide step through the pr
20. the chapters into three major sections The chapters in Part IV focus on how to troubleshoot your network with 7 8 Part Getting Going an eye toward security Chapter 10 covers how to detect and deal with intruders and then describe specific techniques to troubleshoot your firewalls Chapter 11 domain name system server Chapter 12 and modems Chapter 13 Fedora Linux Workstation A Linux workstation is basically thought of as a desktop system used for software development There are well over 100 software packages that come with Fedora Core that fall under the heading of development packages see Figure 1 3 for an illustration of software development package groups in Fedora Development Development Tools 50 50 Details These tools include core development tools such as automake gcc perl python and debuggers 4 Kernel Development 5 5 Details Install these packages to recompile the kernel X Software Development 20 20 Details These packages allow you to develop applications for the X Window System 4 GNOME Software Development 44 44 Details 08 Install these packages in order to develop GTK and GNOME graphical applications KDE Software Development 20 20 Details Y Install these packages to develop QT and KDE graphical applications Figure 1 3 Software development tools are spread across more than 100 software packages in Fedora Troubleshooting skills needed
21. the tools for managing software packages are the same as those in Fedora and other Red Hat Linux systems As a Red Hat Linux troubleshooter transitioning your skills to SUSE you will need to learn about differences in software packaging system administration and installation tools provided by the YaST facility in SUSE and licensing and support issues These and other features that you need to understand to transition from Fedora and Red Hat troubleshooting practices to SUSE troubleshooting are covered in Appendix B Debian Linux When Red Hat Inc dropped the official Red Hat Linux product Debian Linux was one of the first distributions that people evaluated as an alternative to Red Hat particularly for small business servers The Debian stable distribution with the code name Woody has a reputation for being rock solid if slightly slow in implementing the latest Linux software Preface IX Despite its stability however some consider Debian to be less suited for mission critical applications because it doesn t have big company support behind it such as Red Hat and Novell Installation is not as simplified as you will find in Red Hat distributions Likewise hardware detection can require more manual activity than it does in Red Hat On the whole Debian has a stronger draw for people who are more technically inclined You won t find as many books or support options available with Debian as you will with Red Hat systems but
22. to Samba aaao 396 Troubleshooting Security Modes aoaaa a 397 Troubleshooting homes Directory Sharing 399 Troubleshooting Printer Sharing oaaae 399 Name Service Problems in Samba oaoa 400 No Server Access cu a A Ro es GA e eae Nike does 401 Performance Problems een 402 Troubleshooting File Permission Problems 402 Samba Resources sca e ds AA HA mm Sed a De See AE eS 403 Summary gt cee cielo A SR AS URL SURE Bak A es 405 Chapter 16 NFS Troubleshooting lt lt lt 407 ConfigurinsNES sis menya m arar a ere S4 407 The NESISeryer Sermos E epe c o SEN A Eee xS 408 TRENES Client a exem en fee teat Seto a igre Ao eee met deme 410 NFS User Permissions e 412 Troubleshooting NF ee 414 Export FailureS s x so rs A Roe oH 414 Unmount Failure 2 ee 415 MountFailures ee 416 File and Directory Permissions o 417 Performance ls SloW 222r 417 Unexpected NFS Behavior 2 0 ee 418 Monitoring NFS Behavior 0 00000 000005 419 NFS Troubleshooting References 0 00 eee nee 422 Summary sa Pete yb aoa ee he Pe 3 b OR Ne AR ERU ee NO E 422 Part VI Troubleshooting External Services Chapter 17 Web Server Troubleshooting 427 Apache 2 0 An OvervieW e 427 UNIX Threading e 42
23. tracing down a problem There are commands that come with many software packages that let you check the status of a feature and see what is broken The trick is to know where the troubleshooting tools are and how to use them Troubleshooting Fedora and Red Hat Linux We chose Fedora Core 1 as the Linux operating system to illustrate Linux troubleshooting We go through some of the reasoning behind this choice in more depth in Chapter 1 Basically however we chose Fedora because we felt it was the best free Linux you could use to learn troubleshooting techniques that would span from home desktop systems to corporate enterprise computers VIII Preface Despite many people s fear that Fedora Linux might lack quality without official long term support from Red Hat Inc we found the first release of Fedora Fedora Core 1 to be quite reliable There is also a strong and growing community to support Fedora Linux distributions If your goal is to be a professional Linux system administrator learning Fedora will help you learn skills that are immediately transferable to Red Hat Linux versions 8 and 9 in particular as well as Red Hat Enterprise Linux version 3 in particular All of those operating systems use the same installer Anaconda graphical administration tools and desktops bluecurve theme on KDE or GNOME desktop environments You may want to build a business around providing computers installed with Fedora distributions to smal
24. trade dress are trademarks or registered trademarks of John Wiley amp Sons Inc and or its affiliates in the United States and other countries and may not be used without written permission Red Hat and Fedora are trademarks of Red Hat Inc Used by permission Linux is a registered trademark of Linus Torvalds All other trademarks are the property of their respective owners Wiley Publishing Inc is not associated with any product or vendor mentioned in this book About the Authors Christopher Negus is the author of Red Hat Linux Bible all editions Linux Toys and dozens of other books on Linux and UNIX systems Chris began his career writing about UNIX systems at AT amp T more than two decades ago His work with AT amp T included an 8 year run with Bell Laboratories and UNIX System Laboratories where he worked directly with the developers of the UNIX System V operating system Later Chris followed the UNIX source code to Novell Inc in Utah where he helped develop UnixWare documentation and wrote several books on UNIX and UnixWare Thomas Tweeks Weeks holds a BS EET Telecom degree from Texas A amp M has worked for several large government and IT security contractors in the positions of Test and Integration lab coordinator and general sysadmin sysadmin technical trainer and course developer as well as electrical and systems engineer He has been working with Rackspace Managed Hosting since 1999 in the roles of Sys Admin
25. 0 Using server status to track performance 0 4 452 Apache Troubleshooting o 452 Apach R sourees ii d ee ue Xe 453 SUMMA Y conse aa el ee Se Whe eke Dae Sid 454 Chapter 18 File Transfer Troubleshooting 455 Which File Transfer Method To Use 0 2 000080 eee 455 EIPLIILCer A Ad ees oad 455 sep and sftp uu V aep a Bye a A WY oe oos edo 456 WebDAV ho a 5 o ou bv une NUR E bees 457 Configuring and Using FTP o 0202 eee ee o 457 Restricting Access to FTP o o 459 Configuring Environmental Variables 460 Passive BYP oia A A e E XQ 461 Configuring and Using scp and sftp o len 462 OpenSSH and Fedora Core ees 463 Using SGP o A ne A ele mA aa wy as 467 User Clients 4 2 tse tg a li RO ee eae Bee da 472 SSH and Firewalls s s gt ecce loe p d RR TRY 473 Configuring and Using WebDAV o o 474 Defining a WebDAV Share o o e e 475 Securing WebDAV with SSL a 478 Other File Transfer Solutions e e 479 Network Based tar Backups 479 Keeping Multiple Servers in Sync llle 480 File Transfer Troubleshooting o een 482 File Transfer Resources e 483 Summary lona ao Bars A e Re Ih ee als E ee uoces ALTE Y Ae dece e a 484 Chapter 19 E Mail
26. 0 00020 eae 37 SUMMAry uuo qd a RI LM oe A A ae Oe Dos x NU S ee 37 XVIII Contents Chapter 3 Updating and Upgrading Fedora 39 Keeping Fedora Core Up to Date 2e 39 Using Automated Updates o ee ee 40 Manual Updates i n e p coe cose t e aa u e a a E e e a a 46 Source Updates s du Bog dd Bot ae uA het elias ata 51 Troubleshooting Update Problems lees 51 Upgrading to Fedora Core e 51 Troubleshooting Upgrade Problems e 58 Updating a Ximian Desktop 0 00002 pee eee 58 Checking Third Party Updates 59 Breaking Graphics Drivers o e e o 59 How to Keep Your Current Red Hat Linux Systems Running 59 Fedora Legacy i sf A Betas dee ea ace e ie ate 60 Progeny Linux Systems eee ee ee 60 SUMMA it ee At ae ug ee ee e ote a t es IN ae Sk 61 Part II Preventing Problems 63 Chapter 4 Securing and Automating Desktop and Server Installs 65 A Kickstart OvVervieW e 65 Starting Your Kickstart Templates 2 2 eee ee ee 66 Looking Inside Your ks cfg File o a 66 Network Enabling the ks cfg File o cles 70 Using the Red Hat Kickstart Configuration Tool 71 Saving Your ks files 2A 73 Locking Down Desktops and Servers 2n 73 Identifying Your Enterprise Desktop Needs
27. 7 New Build System 0 00 a A aA See 428 Multiprotocol Support 222A 428 Better Support for Non UNIX Platforms 4 428 New Apache API o iuo xw Bh E RS s 428 IPVO Support cocum au due Rem ay WAGERS 428 Filtering ee ay hc i ue Se eS ME ERU eor n ESSA ps dE E Rs 429 Multilanguage Error Responses o 429 Simplified Configuration a 429 Contents Separate Configuration Files for Apache Applications 429 Updated Regular Expression Library 429 Apache Configuration se ee a eoa a ea e a a e ee 430 Configuration FileS o o e 430 Los Files a uv A Hoe oe Bee 430 Other Pilesws s ada e a A a A A E Wee dis 431 httpd conf re rd A epe RUP SON e RE Hon et 431 Common Apache Usage 00 ee 437 Migrating from Apache 1 x to 2 0 o 02000002 eae 439 Apache 2 0 Tips and Tricks o e eee eee ee eee 440 Testing the Configuration File les 440 Controlling User Access po RI ee ERA 440 Restarting versus Reloading Apache cll o 442 Listing Virtual Host Settings ee 443 Listing Apache CompileTime Options 443 Defining Web Directory Permissions c 444 Tweaking Apache for Higher Loads 448 Server Loads and Hardware Requirements 00 449 Benchinarking 420v oa See hee ha WIRE E da 45
28. Corporate Technical Trainer and has acted as liaison between customer support security product engineering departments Tweeks has also been president of the San Antonio user group X otic Computer Systems of San Antonio xcssa org since 1996 Credits Acquisitions Editor Debra Williams Cauley Development Editor Sara Shlaer Production Editor Eric Newman Technical Editor Francois Caen Contributing Author Jesse Keating Editorial Manager Mary Beth Wakefield Vice President amp Executive Group Publisher Richard Swadley Vice President and Executive Publisher Bob Ipsen Vice President and Publisher Joseph B Wikert Executive Editorial Director Mary Bednarek Permissions Editor Laura Moss Media Development Specialist Kit Malone As always I dedicate this book to my wife Sheree C N To my loving and supporting wife Teri who likes firewalls especially green ones Without her I would be an incomplete geek T W Preface Smite install screens rich desktop interfaces and GUI administration tools have made Linux an easy operating system to use unless something goes wrong If installation fails you might find yourself figuring out what kernel options to add at an installation boot prompt If you check a Linux forum with a server problem most times your friends will push aside your graphical tools and have you type shell commands and hand edit configuration file With official support options
29. Fix lf you believe that you have a code fix or other solution to the problem it s a good idea to submit that fix along with the bug report Red Hat Inc recommends that most fixes be delivered in the form of unified diffs so the maintainer can see exactly what code changes you are suggesting After you have entered the bug report you are given an opportunity to attach a patch or other text to the bug report Select Create an Attachment and enter the filename of your patch and a brief summary description along with the attachment I can t stress enough how important it is to enter bug reports to get important fixes done When a package maintainer goes through the list of fixes needed to a software package a report entered into Bugzilla will carry a lot more weight than ranting in a mailing list or just firing off e mails to the maintainer Bug reports make for orderly fixes Joining Fedora Projects The Fedora Project website already lists a variety of software projects you can become involved with Signing on to one of the Fedora mailing lists described earlier in this chapter is a great way to connect up with the people at Red Hat Inc who are running the ongoing Fedora projects Some of the best features of Red Hat Linux that have made their transition over to Fedora are the Red Hat installation program the graphically oriented redhat config tools called system config in Fedora Core 2 and the Red Hat desktop Current projects be
30. Linux Troubleshooting Bible Linux Troubleshooting Bible Christopher Negus and Thomas Weeks WILEY Wiley Publishing Inc Linux Troubleshooting Bible Published by Wiley Publishing Inc 10475 Crosspoint Boulevard Indianapolis IN 46256 www wiley com Copyright 2004 by Wiley Publishing Inc Indianapolis Indiana Published simultaneously in Canada eISBN 0 7645 7716 6 Manufactured in the United States of America 10987654321 No part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording scanning or otherwise except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act without either the prior written permission of the Publisher or authorization through payment of the appropriate per copy fee to the Copyright Clearance Center 222 Rosewood Drive Danvers MA 01923 978 750 8400 fax 978 646 8600 Requests to the Publisher for permission should be addressed to the Legal Department Wiley Publishing Inc 10475 Crosspoint Blvd Indianapolis IN 46256 317 572 3447 fax 317 572 4447 E Mail permcoordinator wiley com LIMIT OF LIABILITY DISCLAIMER OF WARRANTY THE PUBLISHER AND THE AUTHOR MAKE NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS WORK AND SPECIFICALLY DISCLAIM ALL WARRANTIES INCLUDING WITHOUT LIMITATION WARRANTIES
31. Mail Bounces due to Dynamic IP Configuration 511 PostFix OVerview ue o ure deum nem dee pe tae ae A Hp es eee e 511 PostFix versus Sendmail ees 512 Configuring PostFix s i seride oti 2 513 Sendmail and PostFix Resources ee 517 Summary o io dm A RO aw ae ovg d eR AN ie ee 518 Appendix A Fedora Software Repositories 521 Appendix B Troubleshooting SUSE Linux 525 Appendix C Troubleshooting Debian GNU Linux 545 Getting Going CHA PHT ER Introduction to Linux Troubleshooting In This Chapter Introduction to Linux Li troubleshooting skills that were once useful only troubleshooting for hackers and ubergeeks have become necessities for computer professionals and serious technology enthusiasts Once confined to the computers of free software proponents Linux systems have found Learning Linux their way into desktop computers small office servers hand held troubleshooting with computers enterprise operations and anywhere else computer Fedora processors might be found Using Linux If you can troubleshoot Linux demand for your skills will grow Troubleshooting Bible exponentially in the time to come Despite the fact that there are now scores of different Linux systems Giving back to Fedora the core components of those systems are still strikingly similar The kernel hundreds of basic commands and the a
32. OF FITNESS FOR A PARTICULAR PURPOSE NO WARRANTY MAY BE CREATED OR EXTENDED BY SALES OR PROMOTIONAL MATERIALS THE ADVICE AND STRATEGIES CONTAINED HEREIN MAY NOT BE SUITABLE FOR EVERY SITUATION THIS WORK IS SOLD WITH THE UNDERSTANDING THAT THE PUBLISHER IS NOT ENGAGED IN RENDERING LEGAL ACCOUNTING OR OTHER PROFESSIONAL SERVICES IF PROFESSIONAL ASSISTANCE IS REQUIRED THE SERVICES OF A COMPETENT PROFESSIONAL PERSON SHOULD BE SOUGHT NEITHER THE PUBLISHER NOR THE AUTHOR SHALL BE LIABLE FOR DAMAGES ARISING HEREFROM THE FACT THAT AN ORGANIZATION OR WEBSITE IS REFERRED TO IN THIS WORK AS A CITATION AND OR A POTENTIAL SOURCE OF FURTHER INFORMATION DOES NOT MEAN THAT THE AUTHOR OR THE PUBLISHER ENDORSES THE INFORMATION THE ORGANIZATION OR WEBSITE MAY PROVIDE OR RECOMMENDATIONS IT MAY MAKE FURTHER READERS SHOULD BE AWARE THAT INTERNET WEBSITES LISTED IN THIS WORK MAY HAVE CHANGED OR DISAPPEARED BETWEEN WHEN THIS WORK WAS WRITTEN AND WHEN IT IS READ For general information on our other products and services or to obtain technical support please contact our Customer Care Department within the U S at 800 762 2974 outside the U S at 317 572 3993 or fax 317 572 4002 Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books Library of Congress Cataloging in Publication Data available upon request Trademarks Wiley the Wiley Publishing logo and related
33. Server Troubleshooting 485 Switching between MTAs with the alternatives System 486 Understanding the alternatives System a a a a 486 XXV XXVI Contents Using the alternatives System o o 488 Using GUI Configuration Tools for alternatives 491 Sendmail Configuration e 493 etc mail virtusertable ee ee 496 etc aliases a e UE nue ca Re eur ee 498 Sendmail Tips and Tricks lee 499 Redirecting System Mail ees 499 What Are My Sendmail Settings lel 499 Securing User forward Files 2 500 Looking at the Outgoing Mail Queue o 500 Changing Sendmail Options 500 Diagnosing Sendmail Problems o ess 503 Using Log Files to Diagnose Problems 503 Diagnosing MTA Problems Using Telnet 505 Sendmail Troubleshooting 00 ee eee 506 Not Receiving Expected E mail Volume 4 506 Sendmail Not Accepting Connections 0 0 506 E mail Address Not Deliverable a 506 Trouble in the Queue e 507 POP3 Not Running 4540 o RO ER S RO RR RUE a 507 Top Sendmail Problems and Solutions len 509 Blacklisted IP Address a 509 Mail Server Misconfiguration 02 0000 ee eee 510
34. You may also enter the honzontal and vertical synchronization ranges for your T b ADI monitor These values can be gt ACC found in the documentation for x a b ASI your display Be careful when entering these values if you b ATE enter values that fall outside b Aamazing the capabilities of your b Acer equipment you can cause p gt Acton systems Inc A damage to your display Only hostes enter numbers in these fields if Horizonta Sync 31 5 57 0 kHz the values in your manual do e Vertical Sync 50 70 bz Restore original values Hae Hal S Release Notes a Back I Next Figure 2 2 If your monitor isn t listed on the Monitor Configuration screen choose a generic CRT or LCD display option Configure networking lf your computer has an ethernet interface you can configure that at install time You can just leave the defaults in place so that the computer will be set up as a DHCP client and automatically start up if there is a DHCP server on the network Firewall Red Hat Linux distributions presently all use iptables by default to configure firewalls Selections during installation let you get a same set of rules to begin with with high medium or no firewall security See Chapter 11 for more information on firewalls All firewall features on Red Hat Linux distributions use the iptables service by default Additional languages You can select to have more languages supported t
35. a Linux which in its first release was built from the Red Hat Linux code base The distribution would be re released every 4 to 6 months With the name change and its association with Red Hat Inc changing so suddenly there has been a lot of speculation about what exactly Fedora is and how well it can be relied upon Let s start by separating the facts from the speculation about Fedora Fedora is essentially Red Hat Linux 10 A good case can be made for this statement Up until the last 2 months of the development process what is now called Fedora Core 1 was being developed as the next release of Red Hat Linux Most of the last minute changes had to do with changing logos and expanding access to software repositories which we will discuss later Fedora Core 1 is a solid Linux system Hundreds of bug fixes and improvements were made during the development process There were not a tremendous number of new features added to the Red Hat Linux 9 base By most accounts Fedora Core 1 is a rock solid Linux distribution Red Hat Inc supports Fedora lt is clear that Red Hat Inc wants to create high quality software from the Fedora Project Most of the technology in Red Hat Enterprise Linux 3 matches almost exactly the same software packages in Fedora Core 1 Red Hat Inc plans to use Fedora as a proving ground for its enterprise products It doesn t have the resources to maintain and enhance the entire Linux operating system and r
36. a software packages and having them sanctioned by the Fedora Project are still being developed For more on software package definitions visit the Fedora Project Terminology page http fedora redhat com participate terminology html As I noted earlier you should also keep in mind that there are some and will be more software repositories that will be available that won t fall under Fedora Project guidelines You will be on your own to evaluate the quality and legality of those packages gt Cross See Chapter 3 for more complete information on getting Fedora software packages and ia updates See Appendix A for a list of popular third party software repositories A Giving Back to Fedora Contributing to the open source community is the best way to ensure that Linux in general and Fedora in particular will continue to improve and grow in the future Even if you are not a kernel hacker or a software developer at all there are plenty of other ways you can contribute Finding Bugs and Filing Reports The easiest way that anyone using Fedora can help improve it is to report problems As you use Fedora you will certainly bump into things that don t exactly work right Using a facility called Bugzilla which is maintained by Red Hat Inc for the Fedora Project you can Search You can search the Bugzilla database to see if anyone has encountered the same problem you have If someone has there may already be a workaround
37. and special characters you need such as an umlaut or a circumflex not being available Mouse Generic mouse selections based on your mouse type serial USB and so on will probably work in most cases However if your mouse device offers a wheel or special buttons look for an exact match by manufacturer and model to get those features working correctly Figure 2 1 shows an example of the Mouse Configuration window during Fedora Core installation Monitor lf you can t find an exact match for your monitor consider using a generic selection based on screen resolution and monitor type such as CRT or LCD If you can t get a selection to work try some of the options suggested in the troubleshooting tips ahead such as vga After that consider running installation in text mode and dealing with the issue later see Chapter 7 for information on troubleshooting video cards and monitors Figure 2 2 shows the Monitor Configuration screen during installation Upgrade or new install Issues related to upgrading to Fedora from an earlier Red Hat Linux distribution are described in Chapter 3 Figure 2 3 shows the Upgrade Examine screen during installation Chapter 2 Troubleshooting Installation 21 Fedora gt Mouse Configu ration Select the appropriate mouse for the system Choose the correct mouse type Model Bus Mouse for your system C7 Mouse senal old C7 type Do you have a PS 2 USB Bus CC Series
38. artitions as parted can Getting help during installation During the installation process you can view online help text by pressing F1 F2 F3 F4 F5 or F6 buttons Each provides a different type of help information Reading Release Notes There is a lot of excellent information about the installation process in the Fedora Release Notes To view the Release Notes from within any GUI install screen click the Release Notes button on the bottom of the screen Grabbing install screens During graphical installs you can grab screenshots of any installation screen To do this press Shift Print Screen to save the current screen to hard disk You can repeat this as many times as you like When installation is completed you can find the screenshot s in the root anaconda screenshots directory This feature is not supported in text based installs Note Chapter 2 Troubleshooting Installation 45 Get the ks cfg file for kickstart You can use a kickstart file to answer installation questions so you can run unattended installations of Fedora Core or Red Hat Linux distributions After you have installed Fedora or Red Hat Linux a file named anaconda ks cfg is created in the root directory You can use that kickstart file to reproduce the installation you just completed on another computer Later you can edit the anaconda ks cfg file with any text editor You can also use the redhat config kickstart window to modify that file or cre
39. ate a new kickstart file Refer to Chapter 4 for information on using the kickstart feature to create your own custom installs that you can use to automate the installation process for many computers Getting Linux to Boot After Installation You may find that after you have finished installing Fedora or Red Hat Linux your system will not boot There are several things you can try if that is the case The first suggestion would beto pass options to the kernel After that you can try to go into rescue mode to correct the problem Adding Kernel Options After Installation If you need to add options to the kernel to get the installation process to work you may also need to pass those same options to the kernel after the operating system is installed Otherwise some piece of hardware may not work properly or the entire boot process may fail You can try out kernel options before you add them permanently to your boot loader configuration file Procedures for adding kernel options temporarily and permanently are described in the following two sections Adding Options at Boot Time To try out kernel options before adding them permanently do the following 1 Reboot your computer 2 When you see the boot screen GRUB by default quickly press the arrow key to highlight the operating system you want to boot 3 Press e to be able to edit the boot lines for that operating system 4 Move the cursor to highlight the kernel line and press e
40. be entered as hexadecimal numbers Table 2 2 shows the hexadecimal values for different resolutions and numbers of colors this table is from the Framebuffer HOWTO Table 2 2 Setting VGA Modes 640 x 640 x 800 x 1024 x 1152 x 1280 x 1600 x Colors 400 480 600 768 864 1024 1200 4 bits 0x302 8 bits 0 x 300 Ox 301 0 x 303 0 x 305 O x 161 O x 307 Ox 31C 15 bits 0 x 310 0x 313 0 x 316 Ox 162 O x 319 0x 31D 16 bits Ox 311 0x 314 Ox 317 Ox 163 Ox 31A Ox 31E 24 bits 0x 312 Ox 315 0 x 318 Ox 31B Ox 31F 32 bits Ox 164 For more information on VGA modes refer to the svga txt file in usr src linux 2 Documentation directory Refer to Chapter 7 for more in depth coverage on troubleshooting video cards Chapter 2 Troubleshooting Installation 27 Laptop Problems Some specific problems known to cause laptop installations to fail in Fedora Core 1 include the following Boot fails on LCD displays Some LCD displays may prevent the installation process from starting To get around the problem you can try disabling the frame buffer as follows boot linux nofb Installation not starting on Sony VAIO notebooks You may need to temporarily disable some PCI devices on Sony VAIO notebooks to get Fedora to install properly Here are options you can try to add to the boot prompt to get installation to work boot linux pci off idel 0x180 0x386 If All Else Fails Even the sections you just read will h
41. ease Notes Most of the documents are available in PDF RPM and HTML tarball formats 4 Red Hat Enterprise Linux Doc Set Manuals for the Red Hat Enterprise Linux products are also available online www redhat com docs manuals enterprise Several of these manuals are quite generic So most of the content in for example Introduction to System Administration System Administration Guide Reference Guide Security Guide and Step by Step Guide would be appropriate for Fedora as well usr share doc Software packages that come with documentation often put that documentation in subdirectories of the usr share doc directory Much of the documentation is in HTML format and so you can read it from your web browser Man pages Traditional UNIX and Linux documentation was done on per component documents referred to as man pages For a Fedora troubleshooter man pages are a great resource for understanding all the options that come with each command Man pages are typically stored in the usr share man subdirectories for commands man1 system calls man2 programming functions man3 special files man4 file formats 11 12 Part Getting Going man5 games man6 miscellaneous components man7 and administration commands man 8 Info pages Like man pages info pages are text based descriptions of components in Fedora However the info utility which displays info pages is more menu oriented than are man pages C
42. ect FAQ click the FAQ link from the home page You can also click the About link to learn about the people and structure that supports the project Getting Fedora Documentation The Red Hat Linux documentation is one component that didn t come across to the Fedora Project In fact one of the major reasons for this book is to fill the void left by the lack of official documentation coming out of Red Hat Inc for Fedora Instead of porting the Red Hat Linux Documentation to Fedora the Fedora Docs project is focusing its first efforts on producing an Installation Guide Beyond that the Fedora Docs project hopes to produce and encourage others to produce smaller tutorial and HOWTO documents Because the first Fedora release Fedora Core 1 was very similar in many ways to the previous release Red Hat Linux 9 and the recent enterprise release Red Hat Enterprise Linux 3 you can find answers to many questions in existing Red Hat documentation for those products Another resource for Fedora documentation is documents that come with each software package in the Fedora distribution itself Here are some places to look 4 Red Hat Linux 9 Doc Set Manuals for installing customizing and administering Red Hat Linux 9 are on the Red Hat website www redhat com docs manuals 1inux You can download the Installation Guide Getting Started Guide Customization Guide Reference Guide Security Guide System Administration Primer Glossary and Rel
43. ee ee 9 Getting Fedora cuco hy o RUE HR Xem RIA Ro els 10 Connecting with the Fedora Project 11 Getting Fedora Documentation 0 00002 11 Getting on Fedora Mailing Lists o a 12 Getting on Fedora Internet Relay Chat 13 Getting More Software 22A 14 Giving Back to Fedora le 15 Finding Bugs and Filing Reports a 15 Joining Fedora Projects o e ee 16 MovingtoFedoraCore2 en 17 SUMMA ce i4 5o rU bow AAA ROW e Ed d S SEE RS 18 Chapter 2 Troubleshooting Installation 19 Understanding Installation es 19 Choosing Hardware ee 23 Random Access Memory RAM 23 Installation Media CD ROM eA 24 Video Cards is so dex Mee es eh ds So Beh usd 25 Laptop Problems 2 a eee 27 IFAM Else Fallo eru Sh eps exe debe Pet ge E a RU See ee 27 Overcoming Installation Problems a 27 Failing to Start the Install Process lens 28 From the Boot ProMpt e 29 Partitioning Problems e 33 General Installation Troubleshooting Tips llle 34 Getting Linux to Boot After Installation lens 35 Adding Kernel Options After Installation 35 Entering Rescue Mode e 36 Installation Troubleshooting Reference
44. elated applications itself Fedora is critical to Red Hat s success Chapter 1 Introduction to Linux Troubleshooting 4 Fedora is a path to Red Hat Enterprise Some people like to use a freely distributed Linux as a means of showing a reluctant boss or IT department that Linux will work in their business With Fedora Core 1 you can demonstrate many of the same features that are in Red Hat Enterprise Linux 3 Future releases of Fedora could be used to evaluate new technologies in which a company may be interested See the description of Fedora Core 2 later in this chapter 4 Fedora offers more software For someone interested in trying software that is outside of the corporate software model such as games audio and video Fedora Core offers dozens more packages than does Red Hat Enterprise Linux It also contains tools such as yum for downloading complete sets of applications from software repositories in Red Hat RPM format Fedora has the latest technology Here s where some of the risks and opportunities lie with Fedora Because Fedora is slated to come out two to three times per year it can incorporate the latest software available for Linux This should make Fedora Core a great operating system for keeping your knowledge and troubleshooting skills up to date However this should also have the effect of making some releases of Fedora less stable You might find yourself picking and choosing a Fedora Core release to use as you
45. elp you take you through the type of hardware and media you should have used to install Fedora or Red Hat Linux it s quite possible that some hardware that is up to specifications will not work If you have gone through the information in this chapter and are still having failures installing Linux I suggest you do the following Bugzilla For now Fedora and other Red Hat Linux distributions all log bug reports into Bugzilla database of Red Hat Inc http bugzilla redhat com Try searching the Bugzilla database for your computer hardware to see if someone else has had trouble installing on it If nothing turns up consider entering a bug report yourself Then track the bug to see how people on the project respond to the report Google Use www google com or your favorite search engine to search for the word Linux along with the name of your motherboard chipset or computer model Although you may not be able to get Linux to install on your particular PC hardware chances are someone else has tried and has shared their experiences on a website or mailing list somewhere Googling might tell you about other peoples results installing on the hardware you have Installation mailing lists There are mailing lists devoted to answering questions about Fedora and Red Hat Linux You can access the Red Hat installation list from www redhat com mailman listinfo redhat install list For Fedora try the general list www redhat com mailman list
46. entering no h1t to the linux boot prompt as follows boot linux no hlt One downside to using the no h1t option is that the CPU stays on continuously This could cause the CPU to overheat especially in situations where you are overclocking the processor Some laptops have bugs in battery query support If the machine crashes while entering a graphical install you can try turning off advanced power management support as follows boot linux apm off Partitioning Problems When you create the disk partitions on which you install your Fedora or Red Hat Linux system you need to make sure that those partitions provide enough space not only for the current installation but also for the space you need for data Here are some tips related to partitioning your hard disk Allow enough total space An Everything installation of Fedora Core 1 can take up about 5GB of disk space So you need to allow at least that much space plus room for your data if you do a complete installation Allow enough space for installation on each partition If you separate your hard disk into multiple partitions to keep areas of the files system be sure to allow enough space in each partition to handle the data needed For example some parts of the file system you may want to assign to their own partitions are bin var home usr and tmp If you have 5GB available for a full install but separate that space evenly across several partitions chances are y
47. g tasks configuring more refined firewalls and setting up boot servers such as DHCP and NIS To find out how you can contribute to the Configuration Tools Project you can start by joining the fedora config list mailing list Desktop Project Red Hat brought the concept of a standard look and feel across the two major desktop environments GNOME and KDE to Fedora in the form of the Fedora Desktop Project The standard Red Hat look and feel is referred to as Blue Curve Particular areas where Red Hat is looking for input related to the Desktop Project is in the area of creating desktop themes creating splash screens and choosing which applications are set up as defaults If you are fond of writing or have enough insight into a feature that you could write a tutorial on it the Fedora Docs Project is looking for contributors As noted earlier you could join the fedora docs list mailing list to find out more There is also an ongoing effort to find people to translate Fedora into different languages The fedora trans list mailing list is a good way to get further information Moving to Fedora Core 2 Fedora Core 2 reflects Red Hat s commitment to making the Fedora Project a platform for rapid development and adoption of Linux technology Although we are recommending Fedora Core 1 as a more stable Linux distribution to follow along with this book you may want to use Fedora Core 2 to take advantage of some of its new features If you are
48. ges that are not in Fedora Core High quality software packages in RPM format are already available from yum and apt repositories The www fedora us site which merged with Red Hat Linux to form the Fedora Project has software repositories built for Fedora www fedora us wiki FedoraPackageLists The Freshrpms net site is the first place many Fedora users go to get additional software packages There are also other repositories that contain more software that may not meet Fedora s or Red Hat s standards of quality or legality There is a Fedora Project Developer s Guide http fedora redhat com participate developers guide for those who want to contribute their software to the Fedora Project Plans for software packages that don t make it into the main Fedora Core distribution but still Chapter 1 Introduction to Linux Troubleshooting 15 want to be sanctioned to some extent by the Fedora Project can be added to Fedora repositories in one of the following ways 4 Fedora Extras These are additional software packages that don t replace any of the basic Fedora Core packages Eventually the www fedora us site is slated to hold an official set of Fedora Extras packages 4 Fedora Alternatives These are software packages that can replace existing software packages that are in the Fedora Core Fedora Legacy These are packages that contain fixes to older versions of Fedora Core software The guidelines for submitting Fedor
49. han just the one you chose during installation Date and time zone If the computer has an Internet connection you can use network time protocol NTP to automatically keep your computer s clock correct You need to choose your time zone Root password At least one user root is required for every Linux system You enter and verify the root password here Packages With custom installs you can go through and select the exact set of software packages you want to install Boot disk lf your computer has a floppy disk drive you have the option of creating a boot disk which is recommended Chapter 2 Troubleshooting Installation 23 0 Upgrade an existing installation Upg rade Examine e a Choose this ortior if you would like to uporace your existing Fedora Core system This option will preserve the existing data on your drives The installation program has detected a previous installation of The following Red Hat product will be upgraded Fedora Core on this system Fedora Core 1 jdev hda3 Y Wauld yau like to upgrade your system or perform a fresh E Install Fedora Core installation C 23 Choose this optior totreshly installyour system Existng softwa e nd data may be overwrinen depending on your con iguration choices If you choose to upgrade your system make sure that the version of Fedora Core being upgraded is correct To perform a fresh installation select Perform a new Fedora
50. hecking Documents with man and info The man and info commands are used to display man pages and info pages respectively For example to see the man page for the cat command type if man cat To start the info utility you can simply type the info command From there scroll up and down to find the command or other component that interests you With the cursor on the item you want press Enter to display the information Finding Documents in Software Packages If you would like to see what documentation is included with a particular software package you can use the rpm command For example to see what documentation comes with the bash shell software bash package you could type the following if rpm qd bash less This command will show you any manual pages HOWTOs release notes or other documents associated with a Fedora software package Checking Project Sites Nearly every project represented by software packages in Fedora has its own website at which you can find further information and documentation on the project You can usually find the address of a project s website by checking the README file or the RPM description that comes with the software package in Fedora For example to find out about the Rhythmbox multimedia player in Fedora I paged through the Rhythmbox README file less usr share doc rhythmbox README In that file I saw that the official website is http web rhythmbox org and that there is a mail
51. hell o 139 Using Fancy Shell Tricks 2 2 o o e 140 Obtaining Root Privilege o e o 151 Getting Root Access from the Shell o o 151 Getting Root Access fromthe GUI o o lens 153 Examining System Processes e 153 Tracking Processes with Top o e e 154 Tracing down Failed Commands with strace a 156 Going into Rescue Mode e 157 Detecting and Configuring Hardware o llle 159 Using Kudzu to Detect Hardware o 159 Configuring Hardware Modules llle 159 XX Contents Using Network Troubleshooting Tools 162 Remote Login and Execution with ssh 163 Monitoring the LAN with Ethereal 164 Keeping a Session Active with Screen o 165 Trying Network Troubleshooting Basics o 165 SUMMA E Y RR a ee UL A O A qu 166 Chapter 7 X Troubleshooting Video Mouse and Keyboard 169 Beginning with X Video Mouse and Keyboard 169 Configuring Video Mouse and Keyboard lll less 170 Configuring Video Keyboard Mouse during Installation 171 Configuring Video Card after Installation 172 Configuring the Keyboard after Installation
52. her you are supporting dozens of desktop systems or just a few this book covers how to troubleshoot installation Chapter 2 your video card mouse and keyboard Chapter 7 and software packages Chapter 8 Chapter 4 tells how to lock down a Fedora desktop system and Chapter 3 describes how to get critical updates for your desktop system Fedora Linux Servers All the basic server features that came with Red Hat Linux are in Fedora Core Graphical configuration tools developed for Red Hat Linux are included in Fedora Core as are a variety of commands and graphical utilities for troubleshooting your servers Figure 1 2 illustrates the categories of server software in Fedora from the Package Management window Despite the lack of guarantees from Red Hat Inc for supporting more than a short update period for Fedora systems a group of people committed to using Fedora as a server have rallied around the Fedora Legacy Project see Chapter 3 for details Their goal is to provide the long term support for Fedora that it needs to be a viable server operating system Chapter 1 Introduction to Linux Troubleshooting 7 Server Configuration Tools 12 12 Details A a This group contains all of Red Hat s custom server configuration tools KE Web Server 17 17 Details These tools allow you to run a Web server on the system 7 Mail Server 8 8 Details lt gt These packages allow you to configure an IMAP or Postfix es
53. here are also other lists that might interest you Fedora devel list contains information on newly built packages and lets people comment on feature changes For development issues related directly to configuration tools there is fedora config list If you want to contribute to the Fedora documentation effort you can join fedora docs list Getting on Fedora Internet Relay Chat If you have never used Internet Relay Chat IRC before it offers a great way to participate in or just watch discussions by typing messages to a scrolling list Messages are transferred in real time so anyone on the IRC channel can participate right at the moment The Fedora Project offers several IRC channels through the Freenode IRC Network www freenode net Channels include Fedora general chat fedora Open to end users or any participants in the Fedora Project 14 Part Getting Going 4 Fedora development chat fedora devel For chatting about problems and suggestions related to Fedora software development Fedora problem reporting chat fedora bugs To talk about bugs you encounter while using Fedora and find out if workarounds or fixes are available There is also a Spanish language chat channel fedora es and other public and private channels associated with Fedora projects If you have not used IRC before refer to an IRC tutorial such as the one at www irchelp org irchelp irctutorial htm Here s a quick procedure for get
54. ie beneath the surface of Linux Even if it s just in the area of fun projects such as those included with Linux Toys www linuxtoys net learning to troubleshoot Fedora can be a useful skill Figure 1 4 illustrates the Linux Toys Television Recorder Player channel 4948 ES Cusxable Y WebvCRe 09 27 Now on Tv Mozilla REA ARES oer ee NT oo Yd MON He a 3 amp PEE Back Fawad Reload stor Prunus muy 0 l nad LPM n 7 July 2003 2 20AM b lt lt While You 53791 ME Frea TBS Were Sleeping station Any Channel zl KBIC ESUN ESPN EIA Ea Figure 1 4 Linux Toys and other hobbyist applications will run on Fedora Core Going with Fedora Without Going It Alone What some seem to forget as they worry about how well Red Hat Inc will support Fedora is that Linux was originally created and supported by a community of open source developers administrators and integrators Right now the community of people and companies out there that are ready and able to support the software that comes in Fedora is as strong as ever While calling Red Hat Inc for every problem with Fedora may not be an option the trick is to know what the Fedora Project itself is offering with the support of Red Hat Inc and how to look elsewhere for the help you need The first thing to do however is to get your hands on Fedora Choosing a Fedo
55. info fedora list Overcoming Installation Problems Note This section takes you through common and some uncommon failures that can occur during installation and provides advice to get through those problems Many of the features for installing Fedora Core or Red Hat Linux are described in detail in Red Hat Linux Bible If you are not familiar with techniques for installing over the network creating install servers making boot floppies doing kickstart installations and other installation topics you can find these and other installation topics covered in Red Hat Linux Bible Information on doing kickstart installations is included in Chapter 4 28 Part Getting Going Note Failing to Start the Install Process There are some cases where you don t even make it to the boot prompt on the installation screen If that s the case here are a few things you can try CD drive not booting Some computers are not set up to boot from a CD This is more often true of older PCs where you were expected to boot from a floppy disk You can often fix this problem by changing the BIOS To change the BIOS boot the computer and look early on for a message that tells you how to enter setup usually by pressing Del F1 or F2 After entering setup look for a place to change the boot order so that your CD drive is first on the list of media to boot at least before hard disk CD drive not found lt is possible that the installation pr
56. ing list at http lists gnome org mailman listinfo rhythmbox devel If you can t find information about the project s website from its README file you can try listing information about the package to find the site For example to list information about the rdesktop package a Windows NT terminal server client you could type the following rpm qi rdesktop Besides showing a description of the package this command showed that the rdesktop website is at www rdesktop org Links from this site point you to documents that describe the protocols used in rdesktop if you want to research further how the software works Getting on Fedora Mailing Lists Many of the resources slated to support the Fedora Project were created to suit its charter to be a community supported Linux While Fedora mailing lists have been churning away happily Chapter 1 Introduction to Linux Troubleshooting 13 from the get g0 community involvement in other areas will by their nature take more time to develop The Fedora Project has an active set of mailing lists that are available through Red Hat Inc To access the mailing lists both archives and e mailed versions are available to everyone visit the following site http redhat com mailman listinfo There is very active participation from Red Hat Inc developers on all of these lists so you can often get information straight from those people developing and making decisions about the direction of Fed
57. ing sponsored by Red Hat as part of the Fedora Project that include these features are Red Hat Installation Program Anaconda lts installation program named Anaconda with both graphical and text based versions has been one of the strong points of Red Hat Linux for the past few years Anaconda also includes a kick start feature that lets someone installing Fedora preconfigure installation selections so that the install can be done with little or no live input Anaconda is written in Python Currently the Fedora Project is asking for bug reports and requests for enhancements for Anaconda If you are interested in contributing to this project I recommend that you join the anaconda devel list and or kickstart list mailing lists to see how you can become involved Configuration Tools Red Hat s own home grown graphical configuration tools many of which also have text based interfaces have made great strides in recent Red Hat Linux and now Fedora releases toward simplitying Linux system administration These let you configure your network file sharing video cards printers and many other features While I count about 40 Red Hat configuration tools there is still room to simplify many other administrative features The Fedora Configuration Tools Project is recommending Chapter 1 Introduction to Linux Troubleshooting 17 a list of features that could benefit from a GUI These include GUI tools for partitioning your disks schedulin
58. ints that are particularly important A Note provides extra information to which you need to pay special attention Note A 2 A Tip shows a special way of performing a particular task or introduces a shortcut to ease your way A Caution alerts you to take special care when executing a procedure or damage to your Caution computer hardware or software could result p ACross Reference refers you to further information on a subject that you can find outside eterence the current chapter L n Reach Out The FedoraTrouble com website contains updates and errata information for Linux Troubleshooting Bible You can also go to that site to download some of the code examples that are contained in this book If you have any questions or comments about this book feel free to contact Chris by e mail at chriselinuxtoys net Thomas Tweeks can be reached at tweeks bible8theweeks org Acknowledgments Chris Negus With the change from Red Hat Linux to Fedora Core and a rampant feeling that those using free Linux systems weren t going to get any official support if things went wrong we wanted to get a Linux troubleshooting book out to you quickly To that end we asked a lot of people to work really hard in a short period of time I was thrilled when Thomas Weeks agreed to coauthor this book His years of experience working with and training the people who support thousands of Red Hat Linux systems at Rackspace Managed Hosting ww
59. ite http fedora redhat com download The site describes the process of downloading verifying and burning the CD images 4 Find a friend Many Linux enthusiasts or Linux user groups will be happy to get you a copy of Fedora Core or any other Linux that you desire Remember Fedora is free and distributable Fedora Core can be installed on most Pentium class PCs Unless otherwise noted all the software needed in this book is available on the Fedora distribution CDs Chapter 2 contains information on installing Fedora Core and tips on troubleshooting installation Chapter 1 Introduction to Linux Troubleshooting To learn about what is new in Fedora Core especially if you want to know the differences between Fedora Core and Red Hat Linux 9 you can refer to the Release Notes document That document describes the hardware requirements for running Fedora provides notes on installing and using Fedora Core and lists new and removed software packages You can get the Release Notes on the first disk of the three CD Fedora Core set or from the Fedora Project website http fedora redhat com docs release notes Connecting with the Fedora Project The best resource for the latest news and policies relating to Fedora is the Fedora Project website http fedora redhat com From that site you can get the latest information on release schedules project objectives and ways of participating in the project You should read the Fedora Proj
60. l businesses schools or nonprofit organizations as many people are doing today Or you may want to learn skills that will transfer easily to large Red Hat Enterprise Linux installations By going through the procedures and learning the tips in this book you will learn tools and techniques to help you trace down and repair problems with Linux as well as learn how to prevent problems before they occur Transitioning to SUSE or Debian Linux You need a Fedora or other Red Hat Linux system in front of you to make best use of the procedures and tips in this book However given the turmoil surrounding Red Hat s changes to the name support options documentation and training for its free Linux system we recognize that some previously faithful Red Hat supporters are now exploring other Linux systems Whether you plan to drop Red Hat Linux distributions altogether or simply have requirements or desire to use other Linuxes we want to help transition your troubleshooting skills to those Linux systems In particular we want to help you understand the challenges you will face moving to SUSE and Debian Linux systems SUSE Linux SUSE is an obvious alternative to Red Hat Linux distributions for those with an eye toward the enterprise Since the acquisition of SUSE Linux by Novell Inc in January 2004 SUSE has become hooked in with the strong established international sales marketing and development resources of Novell SUSE is also RPM based so
61. l lists ACLs a system with SE Linux enabled can finely define administrative control over the files processes and devices in that system By default SE Linux is turned off in Fedora Core 2 18 Part Getting Going X org X server The X server delivered with Fedora Core 2 changed from the XFree86 server to the X server software available from X org While this shouldn t have much impact on the average desktop user who sees mostly the GNOME or KDE desktop environment colored by the metacity window manager and Bluecurve theme it does change some of the tools available for configuring your video cards from the command line Many new packages More than 200 new packages were added to Fedora Core 2 after Fedora Core 1 While many of these packages were added to improve support for application development especially Java applications some new administrative features were added such as IPSEC VPN software replacing cipe and the exim mail transfer agent which could be used instead of sendmail or postfix Summary Despite the change in both name and how it is produced the Linux operating system referred to as Fedora Core is a good free Linux operating system for learning Linux troubleshooting Red Hat s flagship Red Hat Linux product formed the foundation for the new Fedora Core distribution that is available today Linux Troubleshooting Bible is dedicated to bringing you the skills you need to prevent find and fix proble
62. lete partitions on any of your hard disks Advanced users can switch to a different virtual console type Ctrl Alt F2 to get to a shell and then use the fdisk command to work with disk partitions Disk Druid also supports RAID and LVM partitions If you want to resize a partition as well you can use the parted command GRUB boot loader The GRUB boot loader can be configured so you can launch any bootable partition when you boot your computer You can add a password to the boot loader to protect from one who can boot your system and you can include kernel boot options for special hardware needs Kernel boot options are described later in this chapter The LILO boot loader is no longer offered as an option although you can replace GRUB with LILO by installing the lilo RPM package from CD 3 of the Fedora Core 1 installation set 22 Part Getting Going gt In most cases the monitor can be automatically detected If the detectec settings are not correct for tha monitor select tha ight selLrigs Monitor Configuration Y Unorobed Monitor The installation proyram was not able to properly detect your monitor You can either proceed with the currect selection or select a monitor thal best matches the model Monitor 800x609 attached to this system Unprobec Monitor b Generic I CD Display v Generic CRT Display Monito 640x482 Monitor 1280x1024 Monitor 1400x1250 Monitor 1600x1200
63. ley at Wiley for suggesting that I do this project instead of just working on more Linux Toys www 1 inuxtoys net Thanks to Sara Shlaer for keeping us on track with a tight schedule Thanks to Margot Maley Hutchison at Waterside Productions for contracting the book with Wiley and the other writers on this project And finally thanks to my wife Sheree for being my rock and Caleb and Seth for being the best boys a dad could ask for Thomas Weeks am honored to have been asked by Chris to participate in this project He s a great resource to the Linux community and he and I have really come to know each other well during this frenzied project Technical Editor Francois Caen and I used to work together at Rackspace Managed Hosting and have been good friends for years Between our long hours of work during the early years at Rackspace I would try to get his wife to let him come to my ubergeeky LUG ish user group here in town X otic Computer Systems of San Antonio xcssa org But now that Francois has settled into the Tacoma Washington area he has become heavily involved with his own local LUG there taclug org and has been elected president Acknowledgments XIII My point here is that I am a strong believer in that people who use and love Open Source products and specifically GPL products need to contribute back to this planet wide utopian software development model that we ve built in whatever form they can If you have programming
64. ly at risk for not being detected properly Using the vga option at the boot prompt Anaconda can use the video BIOS to modify the display mode being used This takes place before the kernel is even booted to start the install process To display a list of available VGA settings to choose from you can boot the install process using the following vga option boot linux vga ask When you see the first message press Enter to see a list of VGA settings you can choose from and it will appear as follows Press lt RETURN gt to see video modes available SPACE to continue or wait 30 secs Video adapter VESA VGA Mode COLSxROWS 0 OFOO 80x25 1 OFO1 80x50 2 0F02 80x43 3 0F03 80x28 25 26 Part Getting Going CNS 7 Enter node number or OFO5 80x30 OF06 80x34 OFO7 80x60 0100 40x25 scan You can type scan to scan for additional modes or type a mode number from 0 to 7 in the example above to choose a particular mode As an alternative you can choose a video mode directly with the vga option Table 2 1 contains some examples of vga options and the values they represent Table 2 1 VESA Framebuffer Console VGA Value V deo Modes Each Represents vga 69 640 x 480 x 256K vga 71 800 x 600 x 256 vga 73 1024 x 768 x 256K vga 84 640 x 480 x 32K vga 85 640 x 480 x 64K vga 87 800 x 600 x 32K vga 88 800 x 600 x 64K vga 90 1024 x 768 x 32K vga 91 1024 x 768 x 64K The vga values can also
65. m yarrow iso gt myMD5SUM Compare the contents of myMD5SUM to the MD5SUM you downloaded along with the ISO images MD5SUM is a small text file contained in the same directory as the ISOs 4 The most recent recommendation from Red Hat Inc for a command line to burn CD is to use the cdrecord command in dao mode Here s that command line showing how to burn the first Fedora Core 1 CD from the current directory repeat this step for the other two CDs in the installation set 1 cdrecord v dao eject pad padsize 150s yarrow i386 discl iso If you are burning bad copies slow down the burn process even as low as 2x or 4x 4 Use CD R instead of CD RW media Video Cards If your video card or monitor is improperly detected the screen may be too garbled to be able to complete installation Here are some suggestions if the install process is not able to properly probe and configure your video hardware Run the install in text mode linux text After you boot the computer you can fix the GUI using redhat config xfree86 or the XFree86 tools As long as you are able to see the screen in text mode you can continue with the installation This issue is addressed in Failing to Start the Install Process section later in this chapter Try setting the vga option lf you have a nonstandard size monitor or undetectable video card you can try to set the vga option at the boot prompt when you run the install Laptop computers are particular
66. mail server 7 Windows File Server 2 2 Details amp This package group allows you to share files between Linux F and MS Windows tm systems 4 DNS Name Server 3 3 Details This package group allows you to run a DNS name server BIND on the system Z FTP Server 1 1 Details dj These tools allow you to run an FTP server on the system 7 SQL Database Server 5 5 Details This package group allows you to run an SQL server on the system 4 News Server 11 Details This group allows you to configure the system as a news server 4 Network Servers 17 17 Details dj These packages include network based servers such as 3 CIPE DHCP and telnet Figure 1 2 Advanced network server software once in Red Hat Linux is included in Fedora Most of the troubleshooting skills you will gain from this book are aimed at server troubleshooting While we briefly touch on Red Hat specific graphical administration tools techniques for working with server configuration files and command line tools will help you develop a skill set that applies to most Linux and UNIX systems For small office servers and personal servers you can probably use Fedora Core For larger installations you might consider purchasing Red Hat Enterprise Linux server subscriptions In either case the skills for troubleshooting both distributions will be the same In terms of how server topics are covered in this book we have divided
67. ms with Fedora Core in particular The same skills you learn in troubleshooting Fedora can be used for troubleshooting older Red Hat Linux systems and newer Red Hat Enterprise Linux systems as well as a variety of other Linux systems Besides the information in this book there are many other resources available if you want to support Fedora Core systems The Fedora Project itself sponsors several very active mailing lists where you can ask questions about Fedora features development and software fixes And despite not having a full documentation set dedicated to Fedora there are many useful documents from Red Hat Linux 9 Red Hat Enterprise Linux and from individual software projects included on the Fedora Core CDs that can be used to find information that applies to Fedora Because Fedora is a community supported distribution there are many ways you can contribute to the project itself You can start by filing bug reports when you encounter problems The Fedora Project also encourages you to contribute code fixes and request for enhancements to help improve Fedora going forward Troubleshooting Installation A failed Linux installation will stop you cold I ve heard too many stories of people giving up on Linux because they couldn t get it to install In many cases just knowing a few tricks can get you through Installation is one of the most distribution specific features described in this book The topics in this chapter cover ho
68. ng In most cases you don t need to enter any kernel options to get the Fedora or Red Hat Linux installation to work Hardware will be detected properly and same defaults will be set However cases where you would want to add kernel parameters include the following Not able to probe In some cases the kernel is not able to properly identify the hardware you are using or fully determine the features it does or doesn t support Extra tuning Some options that can be passed to the kernel can be used to tune your kernel to make most efficient use of your hardware Override the defaults You may want to access hardware in a different way than it is used by default for example to change the default screen resolution Once you find kernel options that work during installation write down those options You may need to add those same options to the kernel boot process after Fedora or Red Hat Linux is installed so that your system can boot properly see the Adding Kernel Options After Installation section later in this chapter The following sections break down different kernel options you can use at the boot prompt for Fedora and Red Hat Linux installation Selecting Memory Sizes Sometimes CPU bugs old BIOS limitations and other issues can prevent Linux from properly detecting the amount of memory available on your computer Not having all available memory useable by the install process can considerably slow down the install pr
69. ocedure to learn how to troubleshoot a feature We have divided the book into six major parts Part I Getting Going Part I contains the most Fedora specific information in the book In addition to an introductory chapter Chapter 1 the two other chapters in this part describe how to troubleshoot problems installing Fedora Core 1 Chapter 2 and how to get the updates and do upgrades you need to keep Fedora patched and secure Chapter 3 Part II Preventing Problems The two chapters in this part focus on how to prevent problems from happening in the first place Chapter 4 describes how to lock down both desktop and server Fedora systems before you deploy them Chapter 5 focuses on how to prepare good backup policies to protect your data Part Ill Troubleshooting Basic Features Many features that apply to troubleshooting both desktop and server systems are covered in this part Basic tips and tools that can be used to troubleshoot many different Linux features are described in Chapter 6 Chapter 7 tells how to troubleshoot your video mouse and keyboard Tools for managing your software packages and correcting problems are described in Chapter 8 Troubleshooting disks and file systems is covered in Chapter 9 X Preface 4 Part IV Troubleshooting the Network Techniques for making your network secure and keep it running smoothly are contained in this part Security issues are covered in Chapter 10 Chapter 11 tells how
70. ocess The cachesize and mem options can be used to tell the kernel how much memory to use during the install process Before you start installing you can test the amount of available memory using the mem ory test feature See the Random Access Memory section earlier in this chapter for infor mation on using the memtest feature from the installation boot prompt Set CPU cache size lf the kernel can t determine the cache size correctly from the CPU typically because of a CPU bug you can override the level two CPU cache size and enter the proper amount in kilobytes Here s an example where the level two cache is set to 512kB boot linux cachesize 512k Be sure to not set this number higher than the actual available level two CPU cache size Set memory size If you have added memory to an older machine beyond the 64MB limit originally defined in PC BIOS the boot process may not detect that fact Using the mem option you can set how much memory the kernel has available to it Don t set this Chapter 2 Troubleshooting Installation 33 number higher than the actual amount of RAM available or your computer will crash at some point Changing Power Mode Options The h1t instructions tell CPU to change modes to use less power The CPU essentially goes to sleep during some periods of disuse Some older processors particularly 486 processors had problems coming out of this low power mode If you think this is the case for you try
71. ocess might be able to boot the CD from your IDE ATAPI CD drive but not find the drive when it goes to install Fedora To get around this problem you can identify the CD drive from the installation boot prompt For example if your CD driverwere the slave drive on your first IDE controller you could enter the following line to identify your CD drive boot linux hdb cdrom The master on the first IDE controller would be hda the master on the second IDE controller hdc and the slave on the second IDE controller would be hdd Not bootable CD drive lf there is no way to make your CD drive bootable you can create a bootable floppy disk image from the Red Hat Linux or Fedora installation media You can find the bootable floppy disk images on the first Fedora Core CD in the images directory The README file in that same directory provides a brief description of each image No bootable CD drive or floppy An even slimmer possibility is that you have a computer with a nonbootable CD drive and no floppy disk drive at all In that case you might be able to boot installation from MS DOS that s MS DOS directly and not from a DOS window in Windows With DOS running insert the CD into the CD drive and type the following Era IDs D gt cd Y dosutils D DOSUTILS gt autoboot bat Another alternative if your computer has a network connection is a Preboot eXecution Environment PXE install To be able to do a PXE install you must first set up
72. ocess than you can see from the main install screens Using a set of Ctrl Alt keystrokes you can switch to different virtual terminals to see installation related messages or even go to a shell prompt to run commands Table 2 3 shows different key sequences hold Ctrl and Alt keys as you press a function key You can use these same key sequences to switch between virtual consoles after instal lation is completed You can use these virtual consoles to have multiple login sessions even while a graphical desktop is running Table 2 3 Keys for Switching Virtual Terminals Keys Terminal Ctrl Alt F1 Virtual console 1 Contains running installation dialog Ctrl Alt F2 Virtual console 2 Offers shell prompt to run commands as root user Ctrl Alt F3 Virtual console 3 Shows install log messages from installation program Ctrl Alt F4 Virtual console 4 Displays system related messages Ctrl Alt F5 Virtual console 5 Displays other messages Ctrl Alt F7 Virtual console 7 Return to graphical installation screen Changing partitions with fdisk or parted Advanced users can use the parted fdisk or sfdisk commands to change partitions during the installation process itself You do this by changing to a virtual console Ctrl Alt F2 to get to a shell then simply typing the command Some features available through fdisk are not offered with Disk Druid for example more file system types are available through fdisk Disk Druid also cannot resize p
73. ooting the Basic Printer Setup 374 Troubleshooting Remote Printer Access o o 375 Tuning Up Your Printer 377 Top Troubleshooting Tips e 379 Printing Clients Expect LPD and not CUPS 379 Printer Breaks Down with Jobs in the Queue 379 One Guy is Hogging the Printer less 379 Nobody Can Print Outside the Local LAN o 379 No GUI Printer Administration e e 380 Adding a Printer withlpadmin 382 Printer Resources sonos y a ie da ea Oe ege he ew gh we BO 382 SUMMAEYN fc 8 e da dup abe at ebd Kcd hat a kay ede ge amp 384 Chapter 15 Samba Troubleshooting 385 Understanding Samba 000000 e a eee eee eee 385 Samba Users 2 404 a Sees Gere E eed Row deh de Ses 386 Samba Shares ur a es eA ee Bes ee e e 387 XXIV Contents Basic Samba Setup a ede se es Aet 387 Samba Configuration Tool 22e 388 Command Line Configuration 388 SWAT tae tre us mo a do d dardos ted do Cees dias dedico he 390 Configuration Resources 2 00 ee 393 Using Samba eS Ae E ae Ree ge BOR X Y que 394 See Who Is Connected ee 394 CheckanIlPAddress 2222s 395 Check Available Shares lees 395 Samba Troubleshooting Tips e 396 Preventing Outside Access
74. ora Here s a rundown of what you can expect from each of the Fedora mailing lists General Fedora questions fedora list The fedora list is for general questions about Fedora Of the available mailing lists fedora list is the most active If you sign up for this list you can expect 100 to 200 posts per day or more devoted to questions about Fedora Although there are all types of Fedora questions on this list the list is especially good for how do I get and where do I find types of questions Fedora testing discussions fedora test list The fedora test list tracks the development of Fedora software For the troubleshooter this is a good list to talk about software that has broken down and is in the process of being fixed 4 Fedora announcements fedora announce list lf you are using Fedora you should at least subscribe to fedora announce list This list announces the availability of critical updates for your Fedora systems Fedora desktop fedora desRtop list For issues related to troubleshooting desktop problems or discussing desktop enhancements the fedora desktop list is a good place to start Fedora software updates fedora legacy list To get in on discussions of how updates will be available for Fedora and older Red Hat Linux systems as well beyond the officially supported update plans from Red Hat Inc you should join the fedora legacy list To keep up with the ongoing development of Fedora t
75. ou will not have enough disk space where you need it For example usr can require most of that 5GB of disk space itself while bin may require about 5MB of disk space Allow enough space for data on each partition lf you are splitting up partitions on your hard disk be sure that you have taken account of the amount of space you need for data Typically content for your Web server FTP server and other data servers are contained under your var directory User data tends to be store under the home directory 4 Allow for overhead An ext3 journaling file system the default file system typed used by Fedora and Red Hat Linux systems requires about 30MB of overhead for each partition You need to take that into account if you are creating multiple partitions for your Linux installation The boot partition Although a 100MB partition is recommended for Fedora you can get by with a much smaller boot partition if you are tight on space A typical bootable linux kernel will consume between 1 and 4MB of disk space So even with several different kernels if the space is tight you can probably get by with as little as 20MB of space in boot 34 Part Getting Going General Installation Troubleshooting Tips This section contains some random tips to help you through the installation process Note Escaping to virtual consoles During installation it s possible to find out more about what is happening with the installation pr
76. p on doing the needful guys I would also be remiss if I didn t thank my parents and my Creator Mom Dad thank you for bringing me up keeping me engaged challenged and always supporting me Thank you God for carrying me though the rough parts It s to you I give all glory Most of all I want to thank my wife Teri for giving up all the evenings and weekends that it took me to complete my portion of this work Teri I love you and yes I would marry you all over again Contents at a Glance e0c0600000000000000000000000000000000000000000000000000000 Preface vii corde xau ard dtu ex d dex vii Acknowledgments lees xii Part I GettingGoing llle mo 1 Chapter 1 Introduction to Linux Troubleshooting 3 Chapter 2 Troubleshooting Installation ees 19 Chapter 3 Updating and Upgrading Fedora llle 39 Part Il Preventing Problems ooooooooomomo 63 Chapter 4 Securing and Automating Desktop and Server Installs 65 Chapter 5 Preparing for Backups and Migration llle 99 Part Ill Troubleshooting Basic Features 137 Chapter 6 Troubleshooting Tools 22er 139 Chapter 7 X Troubleshooting Video Mouse and Keyboard 169 Chapter 8 Software Package Troubleshooting llle 191 Chapter 9 File System Disk and Power Troubleshooting 211
77. pproach you need to take to track down problems are very much the same among most Linux systems The goals of Linux Troubleshooting Bible are to help you Set up and fix Linux desktop laptop workstation and server systems Develop Linux troubleshooting expertise that can easily transition to many different Linux systems To provide detailed working instructions to learn Linux troubleshooting we chose Fedora Core 1 as the example Linux distribution for this book In fact we are strong proponents of Fedora for those who want to Become proficient in a free Linux distribution that can be used in the same ways that Red Hat Linux was traditionally used Learn how to dig up resources that can help you maintain Linux systems yourself without paying expensive subscription fees Develop a set of troubleshooting skills that will transition up to enterprise quality Linux distributions Most of the techniques described in this book will work exactly the same on Red Hat Enterprise and Red Hat Linux versions 8 and 9 in particular as well In the next section we explain why we believe Fedora is an excellent choice for both learning Linux troubleshooting and for using as desktop and server systems in many situations 4 Part Getting Going Once you have studied the troubleshooting techniques in chapters of this book you may find that you want to spread those skills to other Linux distributions For that reason we pro
78. r server Fedora offers critical updates and patches This has been the biggest concern for those who have been using Red Hat Linux as a server for their businesses or organizations The amount of time that critical updates will be officially supported by Red Hat for Fedora Core is shorter than it was for Red Hat Linux The Fedora Legacy Project www fedoralegacy org as well as other organizations is stepping up to deal with this issue See Chapter 3 for discussions of how to solve the update and upgrade issues with Fedora The bottom line is that Fedora offers great technology in a freely distributed Linux system Yes there are fewer guarantees from Red Hat Inc if you want to bet your business on Fedora However if the prospect of going it alone with Fedora is exciting but somewhat daunting to you we are here to tell you that you don t have to go it alone If you decide to go with Fedora or at least look into it further Linux Troubleshooting Bible is here to give you or help you find the resources you need to support it Finding Opportunities with Fedora If you take the time to learn how to troubleshoot Fedora what kinds of Linux systems can you support with your new skills The short answer is any kind of system you could set up with Red Hat Linux The software in Fedora supports desktop workstation and server systems and is being used for a variety of specialty uses Fedora Linux Desktop As with most Linux and UNIX sy
79. ra Version By the time this book is released Fedora Core 1 would have been available for several months and Fedora Core 2 would just be hitting the market Although versions 1 and 2 are similar in many ways we based most of this book on Fedora Core 1 for the following reasons Fedora Core 1 had gone through nearly a full Red Hat testing cycle before becoming Fedora Core 1 There were not major feature additions over Red Hat Linux 9 while there were many bug fixes that were included 10 Part Getting Going 4 Fedora Core 2 included many major new features and hadn t been out long enough to know if all the major bugs had been fully shaken out yet For these reasons we felt that Fedora Core 1 made a more stable environment for those who wanted to use the skill taught in this book to set up and use reliable desktop and server systems If however you want to use Fedora Core 2 instead with this book here are some of the differences you can expect Fedora Core 2 includes the new 2 6 kernel by default While there are not many features about the new kernel that change how you use Linux it s possible that support for some hardware drivers may not have been carried over to the 2 6 kernel yet The new kernel also has brought some changes in the types of boot media you can use with Fedora Core 2 Refer to http fedora redhat com download for details on installation media and install procedures Allthe redhat config graphical
80. rom the boot grub grub conf file to see if your computer can run with DMA on to improve performance One reported fix for this problem is also to reduce the amount of memory on computers either by physically removing one of the RAM sticks or by making less memory available using the mem option See the Selecting Memory Sizes section later in this chapter for information on the mem option Hangs when installing on SMP system lf your computer hangs while trying to install on a system with multiple processors you can try disabling IO APIC The noapic option causes an SMP kernel to disable some interrupt controller features on multiprocessor computers Here s how to disable IO APIC boot linux noapic If your board doesn t create a working multiprocessor table you might be able to create one manually using the pirq boot option For information on how to do this refer to the 10 APIC txt file in the usr src linux 2 Documentation directory Chapter 2 Troubleshooting Installation Hangs probing PCMCIA devices You can disable the probing of PCMCIA devices by adding the nopcmcia option as follows boot linux nopcmcia Hangs probing Firewire devices You can disable the probing of Firewire devices by adding the nofirewire option as follows boot linux nofirewire Hardware not detected or improperly detected The Anaconda installer does an amazingly good job of probing and identifying your computer s hardware Howe
81. s needed to get each basic feature running Procedures Provides step by step procedures for walking through techniques for troubleshooting a feature When you are done you should have a good sense of how to feel your way around a feature and look for potential problems Tools Provides additional commands options and interfaces for working with a particular feature Once you understand the basic tools needed to work with a feature you should be able to refer to man pages and info pages to get more options you can use with those tools Tips Provides tips for troubleshooting some of the most common problems you might encounter References Provides refererence information to help you find things like the location of mailing lists project home pages and FAQS for the feature being described If you find that you are stuck on a problem you might try one of the many Fedora and Red Hat Linux online forums listed in Chapter 1 for further information Conventions Used in This Book Throughout the book a special typeface indicates code or commands Commands and code are shown in monospace type This is how code looks Preface XI In the event that an example includes both input and output monospace is still used but input is presented in bold type to distinguish the two Here is an example ftp ftp linuxtoys net Name home jake jake Password The following special mark up is used to call your attention to po
82. se you can force Fedora to allow you to upgrade by entering the upgradeany option at the boot prompt as follows boot linux upgradeany Trying Kernel Installation Options There are literally hundreds of options you can pass to the kernel when you begin installation While we go over some of those options here you can find a more complete list in the documentation that comes with the kernel source code For Fedora Core 1 refer to the following file for descriptions of kernel options usr src linux 2 Documentation kernel parameters txt Options you can pass to the kernel are also described in some detail in the BootPrompt HOWTO You can find that document here http www ibiblio org mdw HOWTO text BootPrompt HOWTO 32 Part Getting Going Caution Note Documentation associated with particular drivers can be found in files and subdirectories of the usr src linux 2 Documentation directory For the most part you will not need to add module specific options to the installation boot prompt Special settings that need to be done to individual drivers can be done after installation see Chapter 6 for information on adding loadable modules While most options that you can pass to the kernel from the boot prompt will cause no harm some have the potential for damaging your hardware For example some improper video settings can damage your video card and options that effect CPU activity such as no h1t can result in overheati
83. skills get involved by joining an Open Source GPL based project development group that interests you sourceforge net For others you might just join and support your local user group assist at Linux Install Fests College LinuxFest events or work for an incredible company that believes in and supports Open Source such as Rackspace I could not have done this book without all the others that did their part I would like to thank Chris for having the faith or sheer workload induced stupor to ask for my help on this impossibly quick monstrous undertaking Working with him and Francois both on the book and on helping to host the Linux Toys site 1 inuxtoys net community effort has been a lot of fun I m very glad that our paths all crossed when they did Also big thanks go to Joe Merlino and Kate Wrightson for spending countless hours trying to interpret and mold my raw research into something usable to Sara for listening to my mail list whining about timelines and to Debra for all her work in getting all this contract material worked out for me I would like to thank Rackspace working there is the most fun I ve ever had while getting paid Plus it s such a super rich learning environment to boot It s been a wild ride since 1999 Thanks Rackspace for allowing us to get some of our in the trenches expertise from the Fanatical Support Department in this book This is a great way to give back to the community Dirk Pat Richard kee
84. st86 com Checking Memory After Installation After Fedora or Red Hat Linux is installed you can find out how much memory is being used by checking proc meminfo as follows cat proc meminfo You can also view the contents of proc meminfo using the free command or the top command If you are about to do an upgrade or a fresh install you can compare the amount shown in the cache size line to the Memory line shown in the memtest86 output If not all the memory is being detected you might consider providing the higher amount of RAM as an option when you boot Fedora or Red Hat Linux installation See the Selecting Memory Sizes section later in this chapter Installation Media CD ROM CD ROMs are still the most common medium for installing Linux systems Red Hat Linux 9 and Fedora Core 1 each comes on a set of three CDs that you can get by downloading from the Internet or with books such as Red Hat Linux Bible If you download the CD ISO images on your Chapter 2 Troubleshooting Installation own then burn them on to CDs here are a few tips to help insure that you make good copies of those media Consider purchasing media or getting copies from a friend if you have a dial up connection Even a broadband connection will take 1 to 3 hours for each CD to download Run the md5sum command on each ISO image For example if you downloaded Fedora Core 1 code named yarrow with the images in the current directory type 1 md5su
85. stems Fedora Core uses the X Window System as the foundation for its graphical user interface GUI It also offers the GNOME and KDE desktop environments If you don t want to use a full blown desktop environment you can use other window managers that come with Fedora instead such as the Tab Window manager and Motif Window manager Figure 1 1 illustrates the GNOME desktop including two panels the Nautilus graphical shell and the Konqueror web browser file manager 5 6 Part Getting Going m 3 QQs Eu a 9 54 FM a Y t 4 n A Lon Mew in Honkmarks Lel a A0 2 Start Here Hs 3s bac onward Up top telozd Home Lacahar roo ri 004 amp n Lj mem 5 root s Home 5crearshet png Lruxt resentation sx Folder 81 tams today st 12 15 19 PM Location Edi View Gu Buckmurks Ious Seuinys Mendo Help AQP d PORCHS Ara RRA Location JB hp foro lirmas ioys nel DHorm E Forum F linsa Toys FAQ osile Latest lorum pos ls L3 root s hables ri xv controls J Music Player red tar t ipcse Figure 1 1 Choose between GNOME and KDE desktops based on the X Window System Fedora comes with all the basic desktop applications you would expect to find on a Linux desktop editors web browsers office productivity applications music players and graphics programs Using yum and apt repositories you can add to the hundreds of desktop applications that come with Fedora Core Whet
86. ting into a Fedora IRC channel 1 With a computer connected to the Internet open an IRC client For example in Fedora you can open an X Chat window by clicking the Red Hat menu and selecting Internet gt More Internet Applications IRC Client 2 Add a Nick Name and two alternate nicknames in case yours is taken a User Name and a Real Name and click Connect 3 Once you are connected to the server join the list you choose by typing join and the channel name For example to join the general Fedora chat channel type join fedora Getting More Software While the plans to broaden the range of software available for Fedora are still being developed new features in Fedora already make it easier to get additional software packages for Fedora than it was for Red Hat Linux Right now you can Use up2date The up2date facility that you used to get software updates for Red Hat Linux has been enhanced for Fedora Core Beginning with Fedora Core 1 software repositories created for the yum or apt package managers can be accessed through the up2date facility By default up2date is configured to use yum repositories to get updates for Fedora systems while Red Hat Enterprise Linux systems still use the Red Hat Network to get official updates from Red Hat Inc Use yum or apt The yum package manager which comes with Fedora Core and apt package manager which is easily attainable can be used to get additional software packa
87. to edit the kernel line 5 With the cursor at the end of the kernel line type the options you want to add and press Enter 6 Press b to continue the boot process including the new options If the options you added fixed your problem you can consider adding them to your boot loader configuration file so that they can be used permanently The following section describes how to add kernel options to the GRUB boot loader Adding Options to the GRUB Boot Loader If you have decided that you want to permanently add boot options to your computer and you are using the GRUB boot loader you can put those options directly into the boot grub grub conf file The following example shows what a grub conf looks like
88. to support Fedora Linux workstations are pretty much the same skills you would need to support any desktop system Specialty Fedora Linux Systems Because there are no licensing fees associated with Fedora Core people have already begun using it to create their own specialized Linux systems For example bootable live CD Linux distributions created from Fedora include ADIOS Linux Boot CD http dc qut edu au adios and RPM Live Linux CD http nwst de livelinuxcd Many companies creating devices that use embedded Linux systems have leaned toward Red Hat Linux in the past According to the 2003 LinuxDevices com Embedded Linux Market Survey Red Hat Linux was the preferred Linux source vendor for embedded Linux systems With 14 4 percent of embedded Linux systems being based on Red Hat Linux with only homegrown Linux systems beating it with an 18 percent share Red Hat Linux captured a substantial share of the embedded systems market The fact that most surveyed 63 9 percent considered no royalties as being the most important feature for choosing a Linux distribution for creating their embedded systems means that we can expect Fedora to carry on that tradition Chapter 1 Introduction to Linux Troubleshooting 9 Whether you hope to build your own embedded or other specialty Linux system some day the skills you learn in Linux Troubleshooting Bible will help you not only get your systems working but understand the range of features that l
89. to troubleshoot your firewalls Chapter 12 describes how to troubleshoot problems with serving domain names from a DNS server Chapter 13 covers how to troubleshoot modem problems Part V Troubleshooting Internal Services Network services that are typically offered behind a company firewall are covered in this part The part includes chapters for troubleshooting printers Chapter 14 Samba Chapter 15 and NFS Chapter 16 Part VI Troubleshooting External Services Popular services that are often made available on public networks are covered in this part Troubleshooting techniques are described for web servers Chapter 17 file transfer servers such as FTP Chapter 18 and e mail servers Chapter 19 In addition the book contains three appendixes Appendix A Fedora Software Repositories describes several repositories for Fedora packages Appendix B Troubleshooting SUSE Linux is intended to help transition the Fedora and Red Hat Linux troubleshooting techniques learned in this book to SUSE Linux systems Appendix C Troubleshooting Debian GNU Linux aims at helping Fedora troubleshooters transition their skills to Debian Linux Many of the chapters in Linux Troubleshooting Bible will cover the same basic types of information This information includes the following Overview Provides an overview of the feature being covered in the chapter This often includes a quick review of the step
90. urn them to CD or DVD themselves to use for installation This creates bit for bit the same CDs or DVDs that were packaged with Red Hat Linux 9 boxed set or books on Fedora As an alternative to burning ISO images to CD or DVD you can copy these images to hard disk The Red Hat installation procedures allow you to install images from a local hard disk or by using a network protocol such as NFS In This Chapter Understanding installation Choosing hardware Overcoming installation problems General installation troubleshooting 20 Part Getting Going 4 Software repositories The directory structure of a Red Hat Linux distribution can also be copied into a network server and installed using NFS HTTP or FTP protocols RPM packages that would be on multiple CDs are merged into a single RedHat or Fedora directory depending on which distribution used With the installation CDs in hand or available on a server you begin the installation process by booting from a CD or floppy disk The installation program used on Fedora and all other Red Hat Linux distributions is referred to as Anaconda Here s what happens when you start the installation process A kernel is started with a minimum set of installed drivers and then additional modules are loaded from the initrd initial RAM disk Installation begins using default values graphical install from CD or in a mode you enter at the boot
91. ver if you have reason to suspect that your hardware is not being properly identified you can boot using the noprobe option Before you start a noprobe install you should know what hardware you have in your computer If the drivers are not on the CD you need to have the drivers you need available on floppy Here s how to start a noprobe install boot linux noprobe When prompted you need to select the drivers to match your hardware or provide the drivers yourself on a floppy No floppy to start network or hard disk install Earlier releases of Red Hat Linux required that you create a boot floppy to start an FTP HTTP NFS or hard disk install assuming I suppose that if you have a CD ROM drive you can just install from there In Fedora Core 1 and other recent Red Hat Linux distributions you can start a network or hard disk install from the first installation CD boot prompt using the askmethod option as follows boot linux askmethod After entering your language and keyboard type the installation screen asks you to select the type of install HTTP FTP NFS or hard disk You might want to do this to save yourself from the trouble of inserting each CD Unable to upgrade Any change to the etc fedora release or etc redhat release files depending on which system you are upgrading from may cause the upgrade process to fail to offer you the chance to upgrade your system to your chosen version of Fedora If that is the ca
92. verview 241 Intrusion Detection Tools ee 242 Red Hat Package Manager 22er 242 Fil System Tools s ace he aye de FS ERE V ES US 243 Watching Your System 2 2 2 2222 243 Third Party Tools z x uu m e Um e EGER VR e 244 Verifying Your Files with RPM o 2 000000 00004 245 Using RPM for Maintenance e 245 Using RPM to Check Security e e 247 Creating a Security Baseline e ee 249 Making an RPM Baseline eee 249 Adding chkrootkit Scans o a 251 Automating System Scanning and Notification 252 ASimple Scanning Script eee ee ee 253 Running the Script s ss ce enose t ee ee 255 Automating the Script oaaae 257 Intrusion Troubleshooting 2 258 IthinkIveBeenCracked lens 258 What Should I Do if ve Been Compromised 259 My ISP Is Threatening Me o e e 260 I Thought I Was Covered What Happened 2 261 Intrusion Detection Resources o ee ee 262 Summary is a A ae qm Reve bea e E de BU fe 263 Chapter 11 Firewall Troubleshooting 265 Firewall Theory eee s 266 Ports and the IP Stack o o e 266 Port Assignments 4 4 a Ge x ge RU XN M NE da 267 TCP IP Packet Str ct tes na i gom yo e m Rue ER 267 Firewallsin Action s amp
93. vide two appendixes Appendixes B and C to help you understand the challenges you will face transitioning to two other popular Linux distributions SUSE and Debian For the moment however I recommend that you have a Fedora Core system in front of you or a Red Hat Enterprise Linux system if you care to step through the information laid out in this book Introducing Fedora Linux In September 2003 while in the middle of developing the successor to Red Hat Linux 9 presumably Red Hat Linux 10 Red Hat Inc made a startling announcement It was merging its Red Hat Linux development with Fedora Linux www fedora us into a new initiative The Fedora Project Suddenly it seemed there was no flagship Red Hat Linux product anymore Users would have to choose between the subscription based Red Hat Enterprise Linux and the community supported Fedora Project The Red Hat Linux product in development was renamed and eventually released as Fedora Core 1 Common reactions to the abandonment of Red Hat Linux for Fedora ranged from surprise to confusion to anger As the dust settles however the logic of this move and the potential upside for the open source community has already begun to emerge Learning Linux Troubleshooting with Fedora The Fedora Project is being touted as a Red Hat sponsored and community supported open source project Its mission is to produce a Linux distribution called Fedora Core sometimes also referred to as Fedor
94. w rackspace com have added incredible depth to the content of this book I d like to thank him for the long hours late nights and weekends he consumed to get this book out to you Getting Jesse Keating to write the chapter on upgrading and updating as well as an appendix on Fedora software repositories was another coup As leader of the Fedora Legacy project there is no better authority than Jesse on getting the critical software updates you need to continue to use free Red Hat Linux and Fedora distributions as reliable operating systems My thanks to Jesse for the countless hours spent outside his day job to make this book a reality Special thanks go to Francois Caen spidermaker com whose RHCE skills added a wonderful dimension to his technical editing of the book Rounding out the writing team Kate and Joe Merlino have shown the value of having technically savvy professional writers on a Linux book project The Kate and Joe team had to work through large amounts of raw material from Thomas and myself which I feel they did with great success As any Linux book should I would like to acknowledge Linux kernel developers kernel org and the GNU Project gnu org as major contributors to Linux and the whole open source movement Likewise I would like to thank Red Hat Inc www redhat com and members of the Fedora Project http fedora redhat com for producing high quality Linux distributions Pd like to thank Debra Williams Cau
95. w to fix or avoid problems when installing Fedora Core However because the same installer is used with Red Hat Linux 9 as well as earlier versions and Red Hat Enterprise Linux most of the information contained here will cover those issues as well For other versions of Linux such as SUSE and Debian the installation process is much different However many of the installation troubleshooting concepts passing options to the kernel dealing with unsupported hardware and so on will help you know what to do if you have trouble installing those other Linux distributions See Appendixes B and C for descriptions of SUSE and Debian respectively Understanding Installation Each Red Hat Linux distribution Fedora Core Red Hat Linux 9 or Red Hat Enterprise Linux is made up of groups of RPM packages bootable images and other assorted software and README files These files are commonly gathered together in one of the following forms Sets of CDs or DVDs CDs are the most common medium for installing Red Hat Linux systems although in the coming years DVDs will probably become more popular Fedora Core 1 and Red Hat Linux 9 each consists of three installation CDs and three source code CDs Red Hat Enterprise Linux is packaged in different CD combinations for WS AS and ES installations ISO images These are images created to fit on a particular medium such as CD or DVD Typically users can download a set of ISO images and b
96. y eee 311 DNS Structure it Sew DR e Gy REG XS ue c Om e RC Re e re 312 Master and Slave DNS Servers o ee eee 313 DNS CaGhing enc ssec x E a A uter p ES we 314 Configuring a Master DNS Server 2 2 0 20 0000000002 00048 315 BIND9 Directory Structure ee ee 316 etc named conf ee 316 The localhost Zone File ee 320 Name Service Tools 1 2 0 ee ee 321 Creating Your Own Zone Files 2 0 0000 ee eee 324 Defining Reverse Lookups o een 326 SECUD TIDS erm aras ra A O E a xs 328 Slave BIND9 DNS Servers ee 328 Configuring the Slave Server o o 329 Zone Refresh Settings 22er 330 BIND9 SeCc rityo xeu Pede ww A B EE e XX m 331 Lock Down Your Name Servers 0000 pe eee 331 Running BIND9 in chroot Mode e e 0084 332 Troubleshooting BIND9 and DNS Issues o o 334 The Slave Name Server Is Not Updating Itself 335 Using whois Effectively een 336 A New Alias or Address Record Won t Load 337 Automated DNS Zone File Troubleshooting 338 Troubleshooting Tools lee 338 Contents XXIII DNS and BIND Resources 2A 338 Summary dorm eb OQ S OR RSRUE eh ew v 4 9 RO QUe mupp A 339 Chapter 13 Modem Troubleshooting Le 341 Choosing a Modem 2e
97. you can verify that the contents of the CD have not been damaged by running mediacheck from the boot prompt Even if you have no reason to suspect that the CDs are bad checking the entire set of CDs can help you avoid having to deal with a partially completed installation The mediacheck performs an md5sum checksum of the contents of any of the Red Hat installation CDs you provide Because the exact same content an ISO image is used in an NFS or hard disk install mediacheck allows you to validate those installation media as well To start mediacheck from a boot prompt type boot linux mediacheck CD ROM installation hangs transferring disk image When booting from a CD it is possible that your computer will hang with the message Transferring Install Image to Hard Disk There are two recommended courses to try Turning on DMA for your CD or turning it off completely for your system To turn on DMA for your CD type the following from the installation boot prompt boot linux allowcddma To run the same option for a text based install type 1 inux text allowcddma This also applies to any other option you want to add to a text based install type To try turning off DMA during installation at least to fix the problem type the following at the boot prompt boot linux nodma With DMA turned off installation will go slower but failures may be less likely to occur After Linux is installed you may want to remove the nodma option f

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