Qmail-Scanner and ClamAV HowTo
Contents
1. Slockiile qz then iain WS ade exi cuooe Ug Uu Glia secos Ss Coce Vimeo iam Slocitile call iue Ea exec usr local bin setuidgid qscand path_to_clamd END usr local clamav supervise clamd run file S Create the usr local clamav supervise clamd log run file vi usr local clamav supervise clamd log run bin sh exec usr local bin setuidgid qscand usr local bin multilog t var log clamd usr local clamav supervise clamd log run bin sh exec usr local bin setuidgid qscand usr local bin multilog t var log clamd Appendix B Scripts Appendix C Software qmail _http Avww gmail org netgmail 1 05 tar gz Daemontools ftp cr yp to daemontools daemontools 0 76 tar gz ClamAV Attp prodownloads sourceforge net clamav clamav 0 65 tar z QMAILQUEUE Patch Attp www qmail org top html qmailqueue MailDrop Attp download sourceforge net courier Time HiRes Attp search cpan org search modulez Time HiRes DB File Attp search cpan org search modulezDB File TNEF unpacker Attp sourcforge net projects tnef Qmail Scanner Attp prodownloads sourceforge net qmail scanner qmail scanner 1 20 t MIME type RFC http www ietf org rfc rfc1521 txt number 1521 Appendix C Software download 22 Appendix D GNU Free Documentation License Version 1 2 November 2002 FSF Copyright note Copyright C 2000 2001 2002 Free Software Foundation Inc 59 Temple Place Suite2. Copyright C 2003 WingNET Internet Services Contact Jesse D Guardiani jesse at wingnet dot net Chapter 3 ClamAV Qmail Scanner and ClamAV HowTo lockfile tmp clamd Location of clamd lock file path to clamd usr local sbin clamd Location of the clamd binary BAD EXIT CODE 1 The exit code we use to announce that something bad has happened The following pipeline is designed to return the pid of each clamd process currently running reu eben mes qomeredlatixeE jos bx cues 1 Stoecida o clami S emis ir epeteyo Generic helper functions Basic return cod rror message function die rcode EXIT CODE 1 ERROR MSG 2 aur Gasp CODE ma VOV je wiran echo SERROR MSG 1 gt amp 2 Sela isaac 1522 SAO BADEN O ODE E3L Main ps_clamd ps_clamd S get_clam_pids_pipeline dl Sin Sos eleme Ji Tasa pid_count 0 OIE prc al a Sos clane do OLE o omite Seo MS STORIE GIN rowiaie e il done die rcode BAD EXIT CODE Error pid count clamd process es already t3L ai e Sleekzxle jp than ja USloxeliie at Ie xxi eoe Sou Gus acordo Sra code Winco den Slociurile wemuil steel Y Ed exec usr local bin setuidgid qscand path_to_clamd pitos END usr local clamav supervise clamd run file Create the usr local clamav supervise clamd log run file
3. dvi usr local clamav supervise clamd log run Chapter 3 ClamAV es feuis GLO VC running Qmail Scanner and ClamAV HowTo bin sh exec usr local bin setuidgid qscand usr local bin multilog t var log clamd Make the run files executable chmod 755 usr local clamav supervise clamd run chmod 755 usr local clamav supervise clamd log run Now set up the log directories mkdir p var log clamd chown qscand var log clamd Finally link the supervise directory into service ln s usr local clamav supervise clamd service Note The clamd script will start automatically shortly after these links are created If you don t want it running do the following clamdctl stop To start clamd backup do the following clamdctl start Chapter 3 ClamAV Chapter 4 Qmail Scanner 4 1 What Is Qmail Scanner From the Qmail Scanner website Qmail Scanner is an addon that enables a qmail email server to scan all gateway ed email for certain characteristics i e a content scanner It is typically used for its anti virus protection functions in which case it is used in conjunction with commercial virus scanners but also enables a site at a server site level to react to email that contains specific strings in particular headers or particular attachment filenames or types e g VBS attachments It also can be used as an archiving tool for auditing or backup purposes Qmail Scanner is integrated into the mail serve
4. 4 Omail Scanne re cvcssecsissvecsscccsesdssctessionsesesesduasdesSessacesdensseetecesasedecdessteegsvesdecobessoaseesescestesdacsiveseodenss 10 41 What Ts Omail S Cannery 33 22 tie do e ea ta UE GP EE UE A RES abo se TRES OE 10 4 2 Installing Qmail Scanner Prerequisites esses enne nennen 10 42 1 Maildtop 5 eerie teint e C P RP OUR er e ROTER CERO AT eer 10 4 22 Perl Modules eue pet etd ebore eene pri 10 4 2 3 Mark Simpson s TNEF Unpacker sessi nns 11 4 2 4 Patching qmail RS Idee bee trece iege 11 4 3 Installing Omatl SCanmer ee Ee EIER EE EPIO e fe v tee EP Sade 11 AA Ownetslip re Re ee Deae eedem eer tor ob rr sene adie is 13 A AA CSUN Des iie AEE n pet uite NO 13 Chapter 5 Configuring qmail to Use qmail scanner queue pL e ecce recen eee ee eee ee eene ee eenae 15 5 1 Changing Your Tcp Rules aii e nous asap erre sae dais pida 15 3 2 Increasmeg Your Softlimit t t poteet er rt eere eee e eI EUR eR EET e Rb lala 15 Chapter TE O ICH LRS ODE EESE E A A E E EES EE 17 Appendix A Recommended Reading and Other Resources 18 Appendix ERINTS ETT SERI eet 19 APPENAix ORNIOLRALET CETERO OCT TL 22 Appendix D GNU Free Documentation License ecce eee ee eee eee eere eee te etna sten seen setate setae seta aset ena eaa 23 DT PREAMBEB uai nocet edente recep te ves cute barco edere RU ee Ce eg 23 D 2 APPLICABILITY AND DEFINIT
5. Only one passage of Front Cover Text and one of Back Cover Text may be added by or through arrangements made by any one entity If the Document already includes a cover text for the same cover previously added by you or by arrangement made by the same entity you are acting on behalf of you may not add another but you may replace the old one on explicit permission from the previous publisher that added the old one The author s and publisher s of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version D 6 COMBINING DOCUMENTS You may combine the Document with other documents released under this License under the terms defined in section 4 above for modified versions provided that you include in the combination all of the Invariant Sections of all of the original documents unmodified and list them all as Invariant Sections of your combined work in its license notice and that you preserve all their Warranty Disclaimers Appendix D GNU Free Documentation License 26 Qmail Scanner and ClamAV HowTo The combined work need only contain one copy of this License and multiple identical Invariant Sections may be replaced with a single copy If there are multiple Invariant Sections with the same name but different contents make the title of each such section unique by adding at the end of it in parentheses the name of the original author or publishe
6. is NOT a real virus in the clamav 0 65 test directory and log it to the scan txt log file Now you need to configure the ClamAV daemon clamd for testing vi usr local etc clamav conf Comment out Example line in clamav conf and save clamdscan 1 scan txt clamav 0 65 This should provide output that is similar to the clamscan command you entered above Chapter 3 ClamAV 4 Qmail Scanner and ClamAV HowTo 3 4 Updating Defs Now we need to update our virus definitions Clamscan includes a utility freshclam to take care of this Freshclam automatically changes from root to the clamav user that you created during the installation First create a log file that freshclam can log to touch var log clam update log chmod 600 var log clamupdate log chown clamav var log clamupdate log Now start freshclam freshclam d c 6 1 var log clam update log This checks for a new virus definition database six 6 times a day Check the var log clam update log file It should look something like this ClamAV update process started at Wed Jan 28 17 49 48 2004 masa vel LS us to date wersaoms 19 muges 19987 i Jewels i louileleies ok daily cvd updated version 111 sigs 597 f level 1 builder tomek Database updated 20584 signatures from database clamav net 81 4 91 185 Now add the freshclam d c 6 1 var log clam update log to your startup scripts You can also setup a cronjob to update the Defs every 6 h
7. service Author Jesse D Guardiani Created 09 10 03 Modified 09 25 03 This script is designed to be run under DJB s daemontools package ChangeLog 09 25 03 JDE Changed clamd user to qscand in compliance with the change to qmail scanner 1 20rc3 097 10 03 JDE Created Copyright C 2003 WingNET Internet Services Contact Jesse D Guardiani jesse at wingnet dot net lockfile tmp clamd Location of clamd lock file path_to_clamd usr local sbin clama Location of the clamd binary BAD_EXIT_CODE 1 The exit code we use to announce that something bad has happened The following pipeline is designed to return the pid of each clamd process currently running get clam pids _pipeline ps ax grep E S path_to_clamd grep v grep eis arine SAYS Generic helper functions Basic return cod rror message function die rcode Appendix B Scripts 20 Qmail Scanner and ClamAV HowTo EXIT_CODE 1 ERROR_MSG 2 aie SX CODE sane 0 IR iiem echo SERROR_MSG 1 gt amp 2 echo Exiting 1 gt amp 2 CA SB ADE O ODE Main ps_clamd ps_clamd S get_clam_pids_pipeline aie i Sos Clemet Jp than pid_count 0 for pid in ps_clamd do pid_count expr pid_count 1 done die_rcode BAD_EXIT_CODE Error pid count clamd process es already running Tdi aus
8. tcp smtp file to include the QMAILQUEUE variable vi etc tcp smtp 127 allow RELAYCLIENT OMAILQUEUE var qmail bin qmail queue 10 allow RELAYCLIENT OMAILQUEUE var qgmail bin qgmail scanner queue pl allow QMAILQUEUE var qmail bin qmail scanner queue pl As you can see we use qmail queue for all local deliveries by setting the QMAILQUEUE variable to be the original qmail queue We then changed the local subnet mail deliveries to use qmail scanner queue pl This causes all local subnet SMTP traffic to be scanned by Qmail Scanner and ClamAV The last line of this file scans all inbound emails After adding the QMAILQUEUE variables you must rebuild the cdb file for Qmail tamailctl cdb 5 2 Increasing Your Softlimit If you try to send an email message you will most likely receive an error from your client The error message will say something that includes this 451 qq temporary problem 44 3 0 If you followed Life with qmail you then have a memory limit set in the var qmail supervise qmail smtpd run file Look for the line that contains softlimit It should look similar to this exec usr local bin softlimit m 2000000 This example sets the memory limit for qmail smtpd to 2M After all of your changes qmail smtpd is now running the entire Perl interpreter and ClamAV 2M will never be enough Each system is different and has different require
9. the Document These Warranty Disclaimers are considered to be included by reference in this License but only as regards disclaiming warranties any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License D 3 VERBATIM COPYING You may copy and distribute the Document in any medium either commercially or noncommercially provided that this License the copyright notices and the license notice saying this License applies to the Document are reproduced in all copies and that you add no other conditions whatsoever to those of this License You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute However you may accept compensation in exchange for copies If you distribute a large enough number of copies you must also follow the conditions in section 3 Appendix D GNU Free Documentation License 24 Qmail Scanner and ClamAV HowTo You may also lend copies under the same conditions stated above and you may publicly display copies D 4 COPYING IN QUANTITY If you publish printed copies or copies in media that commonly have printed covers of the Document numbering more than 100 and the Document s license notice requires Cover Texts you must enclose the copies in covers that carry clearly and legibly all these Cover Texts Front Cover Texts on the front cover and Back Cover Texts on the back cover Both cove
10. 330 Boston MA 02111 1307 USA Everyone is permitted to copy and distribute verbatim copies of this license document but changing it is not allowed D 1 PREAMBLE The purpose of this License is to make a manual textbook or other functional and useful document free in the sense of freedom to assure everyone the effective freedom to copy and redistribute it with or without modifying it either commercially or noncommercially Secondarily this License preserves for the author and publisher a way to get credit for their work while not being considered responsible for modifications made by others This License is a kind of copyleft which means that derivative works of the document must themselves be free in the same sense It complements the GNU General Public License which is a copyleft license designed for free software We have designed this License in order to use it for manuals for free software because free software needs free documentation a free program should come with manuals providing the same freedoms that the software does But this License is not limited to software manuals it can be used for any textual work regardless of subject matter or whether it is published as a printed book We recommend this License principally for works whose purpose is instruction or reference D 2 APPLICABILITY AND DEFINITIONS This License applies to any manual or other work in any medium that contains a notice placed by the copyright hol
11. IONS eee eee e enenenenene nnne einen nent n er senn 23 T 3 VERBACEIMECOPBPY ING tii dina A Teo secs 24 DA COPYINGI N QUANTIE Y 00 A eer hs 25 DS MODIEICATIONS ds 25 D 6 COMBINING DOCUMENTS neroni tieien et oe eA e E ea a e a e eaei aa aal 26 D 7 COLLECTIONS OE DOCUMEBENCES tree ta ertet tete ea pee 27 Qmail Scanner and ClamAV HowTo Table of Contents Appendix D GNU Free Documentation License D 8 AGGREGATION WITH INDEPENDENT WORKS eeeeseeeeeeeeee e eene nennen esser een D2 DIRANSEATION 12 eironi egene EH Fer Hebr e er p bo op ie eco gi breit Ld dante DAO ZTERMINATION 2 erect e Ree cet e Ree reete d dae ul eo te Eee Eee Pd D 11 FUTURE REVISIONS OF THIS LICENSE eere eene nennen D 12 ADDENDUM How to use this License for your documents eee Chapter 1 Introduction 1 1 What This Document Is This document started out as a way for me to document the procedure and required readings for re creating the deployment of Qmail Scanner and ClamAV for my employer s email system I am not a writer or a programmer I am a lowly little systems administrator that got frustrated looking online for all of the information to make Qmail Scanner work with ClamAV This HOWTO will document the steps that I took to get Qmail Scanner and ClamAV to work together Is this the right way to do it Who knows it worked for me There are plenty of snippets of
12. Qmail Scanner and ClamAV HowTo Steve Peace Gregory L Porter version 1 0 Edition Edited by Todd Hawley 09 19 2004 Revision History Revision 1 0 09 19 2004 Initial Release reviewed by TLDP Revision 0 9 08 01 2004 Converted to DocBook Revision 0 4 07 01 2004 First public draft in html Revised by glp Revised by glp Revised by srp This HOWTO describes how to integrate ClamAV an anti virus attachment scanner and Qmail Scanner an anti virus message content scanner with an existing installation of a qmail email server Qmail Scanner and ClamAV HowTo Table of Contents AENA O O 1 LT Wat This Documents abc 1 1 2 What This Document s NO0t iocos ber cet t ier eoa dace p e red teo oa ido ede ua ea igo in 1 1 3 Acknowledgements ere He te tina AE aS 1 1 4 Copytight cu eret Peg beer ast CREE Gua Gna CE RP HEU e ERES EY NS 1 1 5 Disclamiet i ie o ee PC etiem eine 2 LO NEWS E E 2 Chapter 2 AA A 3 Chapter 3 ClamAV 2 eeerseeeoseet ere eed uror seco ene ense e Fora vacseosnccsscuesascseenssvesesseneesssdqssetagcostesedscssnesesesessadevennccssecses 4 Sale Whats EA E 0a VA oo er ree ee rrt ettet dius ra ri resea tue cre Pe EN ER an Ee EA tatiana ER 4 3 2 Installing Clam Vi ER FOE UI Veri b ada Gina 4 9 3 T Sting iro n Udo E ee eer Dent RN Ire te etre t RO ra eid 4 SA Updating Deis ERUNT 5 3 5 Setting up Clamd and Using With Daemontools sees 5 Chapter
13. Res and DB File Perl Modules The modules can be obtained at www cpan org See Appendix C There is a HOWTO there as well that will explain the installation procedure of Perl modules Once again please read the instructions included in the tar balls and review the README information before installing 4 2 3 Mark Simpson s TNEF Unpacker What is TNEF Unpacker This utility unpacks ms tnef type MIME attachments For a better explanation of MIME type attachments please review http www ietf org rfc rfc1521 txt number 1521 Download the package and uncompress the tar ball As with the Maildrop install you should read the INSTALL file included in the tar ball configure make check make install 4 2 4 Patching qmail If you have not already done so please install Bruce Guenter s QMAILQUEUE patch To patch qmail download the patch to your qmail source directory patch pl qmailqueue patch make setup check 4 3 Installing Qmail Scanner We are now ready to install Qmail Scanner Download the latest source of Qmail Scanner As of the writing of this HOWTO it is 1 20 Create a user for Qmail Scanner to run as groupadd qscand useradd qscand g qscand c qmail scanner s nonexistent Unpack the tar ball and change to the Qmail Scanner directory Chapter 4 Qmail Scanner 11 Qmail Scanner and ClamAV HowTo tar zxvf qmail scanner 1 20 tar gz cd qmail scanner 1 20 Run Configure to autodete
14. Sills http www lifewithgmail org qmail FAQ Written by D J Bernstein _hitp cr yp to qmail fag SMTP Simple Mail Transfer Protocol written by Dan Bernstein Attp cr yp to smtp html Daemontools FAQ written by D J Bernstein Attp cr yp to daemontools fag ClamAV FAQ http www clamav net fag html pagestart ClamAV User Manual Written by Thomasz Kojm_http www clamav net doc Qmail Scanner Content Scanner for qmail written by Jason Haar_http gmail scanner sourceforge net Qmail Scanner FAQ Attp qmail scanner sourceforge net FAQ php Clamd daemontools howto written by Jesse D Guardiani http clamav elektrapro com doc clamd supervised clamd daemontools guide txt qmail mailing list archive_http www archive ornl gov 8000 Qmail Scanner list archive_http sourceforge net mailarchive forum php forum qmail scanner general ClamAV users list archive_http news gmane org gmane comp security virus clamav user ClamAV Virus DB list archive Attp news gmane org gmane comp security virus clamav virusdb Maildrop_http www flounder net mrsam maildrop Perl module installation HOWTO _http www cpan org modules INSTALL html Mime type RFC _http www ietf org rfc rfc1521 txt number 1521 Appendix A Recommended Reading and Other Resources 18 Appendix B Scripts These are the scripts contained in this HOWTO They were created by Jesse D Guardiani and can be found in his clamd daemontools HOWTO Clamdctl bin
15. TeX input format SGML or XML using a publicly available DTD and standard conforming simple HTML PostScript or PDF designed for human modification Examples of transparent image formats include PNG XCF and JPG Opaque formats include proprietary formats that can be read and edited only by proprietary word processors SGML or XML for which the DTD and or processing tools are not generally available and the machine generated HTML PostScript or PDF produced by some word processors for output purposes only The Title Page means for a printed book the title page itself plus such following pages as are needed to hold legibly the material this License requires to appear in the title page For works in formats which do not have any title page as such Title Page means the text near the most prominent appearance of the work s title preceding the beginning of the body of the text A section Entitled XYZ means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language Here XYZ stands for a specific section name mentioned below such as Acknowledgements Dedications Endorsements or History To Preserve the Title of such a section when you modify the Document means that it remains a section Entitled XYZ according to this definition The Document may include Warranty Disclaimers next to the notice which states that this License applies to
16. ct what software is installed on your system Review the output to make sure it is correct It should look similar to this configure This script will search your system for the virus scanners it knows about and will ensure that all external programs qmail scanner queue pl uses ar xplicitly pathed for performance reasons It will then generate qmail scanner queue pl e als ma to you o Install aie correctly Continue Y N lt PRESS ENTER gt Found tnef on your system That means we ll be able to decode stupid M attachments The following binaries and scanners were found on your system mimeunpacker usr local bin reformime unzip usr bin unzip tnef usr local bin tnef Content Virus Scanners installed on your System clamuko usr local bin clamdscan which means clamscan won t be used as clamdscan is better Qmail Scanner details log details 0 fix mime 1 debug 1 notify sender admin redundant scanning no virus admin root mail substitute you domain here local domains mail substitute your domain here silent viruses klez bugbear hybris yaha braid nimda tanatos sobig winevar paly Gassen PE lore loan aa Melina Macia Mao llene scanners clamuko_scanner If that looks correct I will now generate qmail scanner queue pl for your system Continue Y N lt PRESS ENTER gt Now type configure install This installs qmai
17. der saying it can be distributed under the terms of this License Such a notice grants a world wide royalty free license unlimited in duration to use that work under the conditions stated herein The Document below refers to any such manual or work Any member of the public is a licensee and is addressed as you You accept the license if you copy modify or distribute the work in a way requiring permission under copyright law A Modified Version of the Document means any work containing the Document or a portion of it either copied verbatim or with modifications and or translated into another language A Secondary Section is a named appendix or a front matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document s overall subject or to related matters and contains nothing that could fall directly within that overall subject Thus if the Document is in part a textbook of mathematics a Secondary Section may not explain any mathematics The relationship could be a matter of historical connection with the subject or with related matters or of legal commercial philosophical ethical or political position regarding them The Invariant Sections are certain Secondary Sections whose titles are designated as being those of Appendix D GNU Free Documentation License 23 Qmail Scanner and ClamAV HowTo Invariant Sections in the notice that says that the Doc
18. edgements Dedications or History the requirement section 4 to Preserve its Title section 1 will typically require changing the actual title Appendix D GNU Free Documentation License 27 Qmail Scanner and ClamAV HowTo D 10 TERMINATION You may not copy modify sublicense or distribute the Document except as expressly provided for under this License Any other attempt to copy modify sublicense or distribute the Document is void and will automatically terminate your rights under this License However parties who have received copies or rights from you under this License will not have their licenses terminated so long as such parties remain in full compliance D 11 FUTURE REVISIONS OF THIS LICENSE The Free Software Foundation may publish new revised versions of the GNU Free Documentation License from time to time Such new versions will be similar in spirit to the present version but may differ in detail to address new problems or concerns See http www gnu org copyleft Each version of the License is given a distinguishing version number If the Document specifies that a particular numbered version of this License or any later version applies to it you have the option of following the terms and conditions either of that specified version or of any later version that has been published not as a draft by the Free Software Foundation If the Document does not specify a version number of this License you may choose an
19. g svc t service clamd echo Restarting clamd svc u service clamd Pr hup echo Sending HUP signal to clamd svc h service clamd Fr help cat HELP stop stops clamd service smtp connections refused nothing goes out start starts clamd service smtp connection accepted mail can go out stat displays status of clamd service restart stops and restarts the clamd service hup same as reload HELP Chapter 3 ClamAV Qmail Scanner and ClamAV HowTo Pr 5 echo Usage 0 start stop stat restart hup help exit 1 PI esac exit 0 Make clamdctl an executable and link to path chmod 755 usr local clamav bin clamdctl fchown clamav usr local clamav bin clamdctl 1ln s usr local clamav bin clamdctl usr local bin Create the supervise directories for the clamd service mkdir p usr local clamav supervise clamd log Now you must create the usr local clamav supervise clamd run file or just copy and paste the script shown below This script was also created by Jesse D Guardiani vi usr local clamav supervise clamd run bin sh run Purpose Start the clamd daemon service Author Jesse D Guardiani Created 09 10 03 Modified 09 25 03 This script is designed to be run under DJB s daemontools package ChangeLog 09 25 03 JDE Changed clamd user to qscand in compliance with the change to qmail scanner 1 20rc3 09 10 03 JDE Created
20. he Title of the section and preserve in the section all the substance and tone of each of the contributor acknowledgements and or dedications given therein L Preserve all the Invariant Sections of the Document unaltered in their text and in their titles Section numbers or the equivalent are not considered part of the section titles M Delete any section Entitled Endorsements Such a section may not be included in the Modified Version N Do not retitle any existing section to be Entitled Endorsements or to conflict in title with any Invariant Section O Preserve any Warranty Disclaimers If the Modified Version includes new front matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document you may at your option designate some or all of these sections as invariant To do this add their titles to the list of Invariant Sections in the Modified Version s license notice These titles must be distinct from any other section titles You may add a section Entitled Endorsements provided it contains nothing but endorsements of your Modified Version by various parties for example statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard You may add a passage of up to five words as a Front Cover Text and a passage of up to 25 words as a Back Cover Text to the end of the list of Cover Texts in the Modified Version
21. heir use in free software Appendix D GNU Free Documentation License 29
22. information that I liberated from many sources Please see the Acknowledgments The most current version of this document can be found at_http stevepeace no ip org 1 2 What This Document Is Not This document is not a comprehensive source of information for ClamAV Qmail Scanner qmail daemontools Linux Un x FreeBSD Perl etc I do not pretend to know everything about everything Like I said before this worked for me it may not work for you If you don t know how to use a particular OS tool or piece of software THIS HOWTO WILL NOT HELP YOU I am a firm believer in RTFM So please make sure that you check out Appendix A and the Disclaimer before following this HOWTO 1 3 Acknowledgments I would like to acknowledge the following people and groups Jason Haar for Qmail Scanner Jesse D Guardiani original clamd daemontools HOWTO The entire ClamAV group for ClamAV Dan Bernstein for qmail and daemontools Dave Sill for Ifwq Bruce Guenter qmailqueue patch Mark Simpson TNEF unpacker Double Precision Inc maildrop CPAN org Perl modules 1 4 Copyright Copyright c 2004 Steven R Peace Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 2 or any later version published by the Free Software Foundation with no Invariant Sections with no Front Cover Texts and no Back Cover Texts A copy of the license is included in the sec
23. l scanner queue pl and creates the necessary directory structures You should see similar messages as before Once again read the output of the script to make sure everything is correct If it is press Chapter 4 Qmail Scanner 12 Qmail Scanner and ClamAV HowTo ENTER to install Qmail scanner If qmail has been installed successfully qmail scanner queue pl should now be installed You should see qmail scanner queue pl in var qmail bin ls var qmail bin var qmail bin gmail scanner queue pl If you do not see qmail scanner queue pl in var qmail bin then execute the configure script again Please pay attention to the output of the script and verify that all of the settings are correct You can also visit the Qmail scanner mail archives at Attp lists sourceforge net mailman listinforgmail scanner general 4 4 Ownership In order for Qmail Scanner to be able to use ClamAV some of the ClamAV ownerships must be changed If you recall we made a clamav user to run ClamAV and then changed the permissions so only the clamav user could run it Now we need to provide the qscand user privledges to use ClamAV First change the ownership of the clamd supervise directories chown R qscand usr local clamav supervise Now change the ownership of the ClamAV log file chown R qscand var log clamd 4 5 Testing Now test Qmail Scanner contrib test instaltion sh doit Sending standard test message no
24. ments It will take some experimenting on your part to find the correct value for your system s softlimit Do not set softlimit to some high value You are asking for trouble if you do this To find the minimal value for your system I recommend the following steps ncrease softlimit by IM e qmailctl restart e Send a message Chapter 5 Configuring qmail to Use qmail scanner queue pl 15 Qmail Scanner and ClamAV HowTo Repeat until you can successfully send an email Once you have found the minimum I recommend increasing that by 1 5M just for times that your email server has a heavy load After that just create a daily cronjob that runs var qmail bin qmail scan queue pl z to cleanup any dropped SMTP sessions that may be lying around in var spool qmailscan Chapter 5 Configuring qmail to Use qmail scanner queue pl 16 Chapter 6 Conclusion After following the instructions in this HOWTO now you can feel confident about your email messages being more secure By implementing Qmail Scanner and clamav you have successfully added another layer of security to your email system and overall anti virus protection Of course there is no such thing as 100 secure email messages Nor will this installation replace sound anti virus practices but it should make those practices a little easier to implement and manage Chapter 6 Conclusion 17 Appendix A Recommended Reading and Other Resources Life with qmail written by Dave
25. mmime from Maildrop 1 3 8 Perl 5 005 034 Perl module Time HiRes Perl module DB File Perl module Sys Syslog Mark Simpson s TNEF Unpacker Bruce Guenters QMAILQUEUE patch Chapter 2 Prerequisites Chapter 3 ClamAV 3 1 What is ClamAV From the ClamAV website Clam AntiVirus is a GPL anti virus toolkit for UNIX The main purpose of this software is the integration with mail servers attachment scanning The package provides a flexible and scalable multi threaded daemon a command line scanner and a tool for automatic updating via Internet The programs are based on a shared library distributed with the Clam AntiVirus package which you can use with your own software Most importantly the virus database is kept up to date 3 2 Installing ClamAV Download the ClamAV source at Attp www clamav net As of the writing of this HOWTO the latest version is 0 65 tar xvzf clamav 0 65 tar gz cd clamav 0 65 groupadd clamav useradd clamav g clamav c Clam AntiVirus s nonexistent configure make make install MEA 3 3 Testing As long as make and make install have finished without errors you are now ready to test your installation If you did experience errors please review the ClamAV documentation that was included in the tar ball You may also try the ClamAV website for some helpful tips To test your installation type pelemscain 2 l scan exc elemev 0 65 Clamscan should find a test virus This
26. ocument well before redistributing any large number of copies to give them a chance to provide you with an updated version of the Document D 5 MODIFICATIONS You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above provided that you release the Modified Version under precisely this License with the Modified Version filling the role of the Document thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it In addition you must do these things in the Modified Version GNU FDL Modification Conditions A Use in the Title Page and on the covers if any a title distinct from that of the Document and from those of previous versions which should if there were any be listed in the History section of the Document You may use the same title as a previous version if the original publisher of that version gives permission B List on the Title Page as authors one or more persons or entities responsible for authorship of the modifications in the Modified Version together with at least five of the principal authors of the Document all of its principal authors if it has fewer than five unless they release you from this requirement State on the Title page the name of the publisher of the Modified Version as the publisher Preserve all the copyright notices of the Document Add an appropriate copyright notice for your modifications adjacen
27. ours if you like dvi etc crontab Q amp 8 se c9 woo usie Local onm elemsceia 3 5 Setting up Clamd and Using With Daemontools Edit etc clamd conf and make the following changes vi etc clamd conf ncomment LogSyslog ncomment StreamSaveToDisk ncomment MaxThreads and change value to 30 ncomment User and change value to qscand ncomment Foreground U U U U U Uncomment ScanMail Create the clamav directory Chapter 3 ClamAV 5 Qmail Scanner and ClamAV HowTo mkdir p usr local clamav bin Now create a startup shutdown script for clamd Copy and paste the script shown below This script was written by Jesse D Guardiani vi usr local clamav bin clamdctl bin sh For Red Hat chkconfig Hesse ns c MEO NE description the ClamAV clamd daemon PATH usr local clamav bin bin usr bin usr local bin usr local sbin export PATH Case WILY size start echo Starting clamd if svok service clamd then sve u service clamd else echo clamd supervise not running joa if d var lock subsys then touch var lock subsys clamd irat Pr stop echo Sirosgsamns E bennek o V echo clamd sve d service clamd if f var lock subsys clamd then rm var lock subsys clamd irat Pr stat svstat service clamd svstat service clamd log Pr restart echo Restarting clamd Geha W Sieejeoume eben svc d service clamd echo Sending clamd SIGTERM and restartin
28. r at a lower level than some other Unix based virus scanners resulting in better performance It is capable of scanning not only locally sent received email but also email that crosses the server in a relay capacity 4 2 Installing Qmail Scanner Prerequisites 4 2 1 Maildrop What is Maildrop From the maildrop web site maildrop is the mail filter mail delivery agent that s used by the Courier Mail Server You will not be using Maildrop or the Courier Mail Server for this installation However Qmail Scanner requires reformmime which is included in Maildrop This is the only reason Maildrop is mentioned in this HOWTO Download and unpack the latest version of Maildrop Please read the INSTALL file included in the tar ball configure make make install strip make install man 4 2 2 Perl Modules Time HiRes Perl module From the README file in the tar ball Time HiRes module High resolution time sleep and alarm Implement usleep ualarm and gettimeofday for Perl as well as wrappers to implement time sleep and alarm that know about non integral seconds DB File Perl module Chapter 4 Qmail Scanner 10 Qmail Scanner and ClamAV HowTo From the README file in the tar ball DB_File is a module which allows Perl programs to make use of the facilities provided by Berkeley DB version 1 DB File can be built version 2 3 or 4 of Berkeley DB but it will only support the 1 x features Download Time Hi
29. r of that section if known or else a unique number Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work In the combination you must combine any sections Entitled History in the various original documents forming one section Entitled History likewise combine any sections Entitled Acknowledgements and any sections Entitled Dedications You must delete all sections Entitled Endorsements D 7 COLLECTIONS OF DOCUMENTS You may make a collection consisting of the Document and other documents released under this License and replace the individual copies of this License in the various documents with a single copy that is included in the collection provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects You may extract a single document from such a collection and distribute it individually under this License provided you insert a copy of this License into the extracted document and follow this License in all other respects regarding verbatim copying of that document D 8 AGGREGATION WITH INDEPENDENT WORKS A compilation of the Document or its derivatives with other separate and independent documents or works in or on a volume of a storage or distribution medium is called an aggregate if the copyright resulting from the compilation is not used to limit the legal rights of the compilation s user
30. rs must also clearly and legibly identify you as the publisher of these copies The front cover must present the full title with all words of the title equally prominent and visible You may add other material on the covers in addition Copying with changes limited to the covers as long as they preserve the title of the Document and satisfy these conditions can be treated as verbatim copying in other respects If the required texts for either cover are too voluminous to fit legibly you should put the first ones listed as many as fit reasonably on the actual cover and continue the rest onto adjacent pages If you publish or distribute Opaque copies of the Document numbering more than 100 you must either include a machine readable Transparent copy along with each Opaque copy or state in or with each Opaque copy a computer network location from which the general network using public has access to download using public standard network protocols a complete Transparent copy of the Document free of added material If you use the latter option you must take reasonably prudent steps when you begin distribution of Opaque copies in quantity to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy directly or through your agents or retailers of that edition to the public It is requested but not required that you contact the authors of the D
31. s beyond what the individual works permit When the Document is included in an aggregate this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document If the Cover Text requirement of section 3 is applicable to these copies of the Document then if the Document is less than one half of the entire aggregate the Document s Cover Texts may be placed on covers that bracket the Document within the aggregate or the electronic equivalent of covers if the Document is in electronic form Otherwise they must appear on printed covers that bracket the whole aggregate D 9 TRANSLATION Translation is considered a kind of modification so you may distribute translations of the Document under the terms of section 4 Replacing Invariant Sections with translations requires special permission from their copyright holders but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections You may include a translation of this License and all the license notices in the Document and any Warranty Disclaimers provided that you also include the original English version of this License and the original versions of those notices and disclaimers In case of a disagreement between the translation and the original version of this License or a notice or disclaimer the original version will prevail If a section in the Document is Entitled Acknowl
32. sh For Red Hat chkconfig wr Chikcomelcg e 30 30 description the ClamAV clamd daemon PATH usr local clamav bin bin usr bin usr local bin usr local sbin export PATH case 1 in start echo Starting clamd if svok service clamd then sve u service clamd else echo clamd supervise not running irat if d var lock subsys then touch var lock subsys clamd f Pr stop exeo eer bees s s echo clamd svc d service clamd if f var lock subsys clamd then rm var lock subsys clamd fE FF stat svstat service clamd svstat service clamd log ad restart echo Restarting clamd echo Stopping clamd svc d service clamd echo Sending clamd SIGTERM and restarting svc t service clamd echo Restarting clamd svc u service clamd PI hup echo Sending HUP signal to clamd svc h service clamd vr help cat lt lt HELP stop stops clamd service smtp connections refused nothing goes out Start starts clamd service smtp connection accepted mail can go out stat displays status of clamd service restart stops and restarts the clamd service Appendix B Scripts 19 Qmail Scanner and ClamAV HowTo hup same as reload HELP Pr 22 echo Usage 0 start stop stat restart hup help exit 1 PI esac exit 0 usr local clamav supervise clamd run vi usr local clamav supervise clamd run bin sh run Purpose Start the clamd daemon
33. t to the other copyright notices Include immediately after the copyright notices a license notice giving the public permission to use mua Appendix D GNU Free Documentation License 25 Qmail Scanner and ClamAV HowTo the Modified Version under the terms of this License in the form shown in the Addendum below G Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document s license notice H Include an unaltered copy of this License I Preserve the section Entitled History Preserve its Title and add to it an item stating at least the title year new authors and publisher of the Modified Version as given on the Title Page If there is no section Entitled History in the Document create one stating the title year authors and publisher of the Document as given on its Title Page then add an item describing the Modified Version as stated in the previous sentence J Preserve the network location if any given in the Document for public access to a Transparent copy of the Document and likewise the network locations given in the Document for previous versions it was based on These may be placed in the History section You may omit a network location for a work that was published at least four years before the Document itself or if the original publisher of the version it refers to gives permission K For any section Entitled Acknowledgements or Dedications Preserve t
34. tion entitled GNU Free Documentation License This HOWTO is free documentation you can redistribute it and or modify it under the terms of the GNU Free Documentation License This document is distributed in the hope that it will be useful but without any Chapter 1 Introduction 1 Qmail Scanner and ClamAV HowTo warranty without even the implied warranty of merchantability or fitness for a particular purpose 1 5 Disclaimer I disavow any potential liability for the contents of this document Use of the concepts examples and or any other information or content of this document is entirely at your own risk All copyrights are owned by their owners unless specifically noted otherwise Use of a term in this document should not be regarded as affecting the validity of any trademark or service mark Naming of particular products or brands should not be seen as endorsements You are strongly recommended to take a backup of your system before major installation and backups at regular intervals 1 6 News The document home page can be found at_http stevepeace no ip org Check here for the most current versions Chapter 1 Introduction 2 Chapter 2 Prerequisites You should already have a working qmail server with daemontools installed Your server will also need ClamAV Prerequisites Zlib and zlib devel packages Gcc compiler 2 9x or 3 x Bzip2 library recommended Qmail Scanner Prerequisites qmail 1 03 Refor
35. ument is released under this License If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant The Document may contain zero Invariant Sections If the Document does not identify any Invariant Sections then there are none The Cover Texts are certain short passages of text that are listed as Front Cover Texts or Back Cover Texts in the notice that says that the Document is released under this License A Front Cover Text may be at most 5 words and a Back Cover Text may be at most 25 words A Transparent copy of the Document means a machine readable copy represented in a format whose specification is available to the general public that is suitable for revising the document straightforwardly with generic text editors or for images composed of pixels generic paint programs or for drawings some widely available drawing editor and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters A copy made in an otherwise Transparent file format whose markup or absence of markup has been arranged to thwart or discourage subsequent modification by readers is not Transparent An image format is not Transparent if used for any substantial amount of text A copy that is not Transparent is called Opaque Examples of suitable formats for Transparent copies include plain ASCII without markup Texinfo input format La
36. viruses done Sending eicar test virus should be caught by perlscanner module done Sending eicar test virus with altered filenam should only be caught by commercial anti virus modules if you have any Sending bad spam message for anti spam testing In case you are using SpamAssassin Done Now check the e mail for your postmaster alias account You should now have 4 email messages in your postmaster s mailbox If you do not have the 4 messages in the postmaster s mailbox then Verify that you are checking the proper mailbox Chapter 4 Qmail Scanner 13 Qmail Scanner and ClamAV HowTo Re execute the configure script for qmail scanner queue pl Verify that the virus admin from the script output is the same as your qmail postmaster alias Check qmail to see if the messages are in the queue If they are try issuing a qmailctl flush command to force delivery If all else fails check the Qmail Scanner mailing list archives at http lists sourceforge net mailmamlistinfo gmail scanner general Chapter 4 Qmail Scanner 14 Chapter 5 Configuring qmail to Use qmail scanner queue pl 5 1 Changing Your Tcp Rules Once everything is installed configured and successfully tested configure qmail to utilize Qmail Scanner and ClamAV If you have followed the instructions found in Dave Sills Life With qmail see Appendix A Reading Resources you should have a tcp smtp file in your etc directory You must edit
37. y version ever published not as a draft by the Free Software Foundation D 12 ADDENDUM How to use this License for your documents To use this License in a document you have written include a copy of the License in the document and put the following copyright and license notices just after the title page Sample Invariant Sections list Copyright c YEAR YOUR NAME Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 2 or any later version published by the Free Software Foundation with no Invariant Sections no Front Cover Texts and no Back Cover Texts A copy of the license is included in the section entitled GNU Free Documentation License If you have Invariant Sections Front Cover Texts and Back Cover Texts replace the with Texts line with this Sample Invariant Sections list with the Invariant Sections being LIST THEIR TITLES with the Front Cover Texts being LIST and with the Back Cover Texts being LIST If you have Invariant Sections without Cover Texts or some other combination of the three merge those two alternatives to suit the situation Appendix D GNU Free Documentation License 28 Qmail Scanner and ClamAV HowTo If your document contains nontrivial examples of program code we recommend releasing these examples in parallel under your choice of free software license such as the GNU General Public License to permit t
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