Univention Corporate Server
Contents
1. Configuration of soft bounces postfix softbounce is set to yes e mails are never returned after a bounce but instead are held in the queue This setting is particularly useful during configuration work on the mail server 15 www univention de univention be open Chapter 9 Handling of mailboxes during e mail changes and the deletion of user accounts A user s mailbox is linked to the primary e mail address and not to the user name The Univention Configu ration Registry variable mail cyrus mailbox rename can be used to configure the reaction when the primary e mail address is changed e Ifthe variable is set to yes the name of the user s IMAP mailbox is changed This is the standard setting since UCS 3 0 If the setting is no it will not be possible to read previous e mails any more once the user s primary e mail address is changed If another user is assigned a previously used primary e mail address she receives access to the old IMAP structure of this mailbox The Univention Configuration Registry variable mail cyrus mailbox delete can be used to config ure whether the IMAP mailbox is also deleted when a user account is deleted In the basic setting the mail boxes are kept when a user account is deleted 16 www univention de univention be open Chapter 10 Distribution of an installation on several mail servers The UCS mail system offers the possibility of distributing users across several mail server2. univention be open Univention Corporate Server Cyrus mail server www univention de univention be open www univention de univention be open Table of Contents Introduction arD ee Pop oe eeaeaaar5_wAarrhrr rf aaaaa r re 4 waar l anrtot zxzzzcctXtw _uew br rr arrbrsrr r rrr bb EUEN EEEE EEEE 5 3 Management of the mail server data LLELL kk kk kK ke kK k ke K kK K kK K KAK KK KK KA 6 3 1 Managemerit of mail domains sci lt lt kkd kcleka dlke lk kadakebe kude c ay de ke bikewe s ade aw k ea sees kk K kkk 6 3 2 Assignment of e mail addresses tO USeTS AhC L Eu Ek kk kK kek k kK K kK K k K kk 6 3 2 Management of mailing lists 5 iyi xu o k ku kelek n deb b k uk h kek ek EEE KHE wep kak c H ket W Eke HE EDE ke K ek 7 3 4 Management of mail groups lt s44x xc 4 41353001544 ke yek0 n beetles neb n Weheb bne neha k e Hes k n kek b e b k a la 7 3 5 Management of shared IMAP folders L kk kk kK k k k kek kK K kK K kK 8 36 M il qUOtA zcr b gg WWkxxogappxo2 9 4 Spam detection and filter sis si ko 1 kne skis ka sk kak dkuE el leu c ket ol KE H k WE kEE Ke E0 U stab EREE K HE KEDE BR RE 10 5 Identification of viruses and malWar i s4 Asissiskk sikkake kak s k xal a e nirearen ones eere bai eneee ee bl i oaj 11 6
3. manual Univention GmbH 2014 Univention Corporate Server Manual for users and administrators http docs univention de manual 4 0 html
4. n k da kek nak 19 PAP ab 2Der iertare eee a Esee EEO AE EEEE ROES EEEREN EEEIEE 20 IZA Emam filters hreannecmenrs dren n e seine e eee T E 21 Bibliography srias na E E E E AEE E EREE O EAE A 22 3 www univention de univention be open Chapter 1 Introduction Univention Corporate Server provides mail services that users can access both via standard mail clients such as Thunderbird and via the webmail interface Horde Note This is the documentation for the Univention Corporate Server mail server component using Cyrus instead of Dovecot as IMAP and POP3 server Since Univention Corporate Server version 4 0 2 Dovecot is used as the default IMAP and POP3 server The documentation for using Dovecot can be found in the main user manual ucs manual Postfix is used for sending and receiving mails In the basic installation a configuration equipped for local mail delivery is set up on every UCS system In this configuration Postfix only accepts mails from the local server and they can also only be delivered to local system users The installation of the mail server component implements a complete mail transport via SMTP see Chapter 2 Postfix is reconfigured during the installation of the component so that a validity test in the form of a search in the LDAP directory is performed for incoming e mails That means that e mails are only accepted for e mail addresses defined in the LDAP directory or via an alias The I
5. Identification of spam sources with DNS based Blackhole Lists DNSBL ees 12 7 Integration of Fetchmail for retrieving mail from external mailboxes L EEEE EE 13 8 Confipuration of the mall Server ss cscce sesutewscnsesaesceediinwsnoousnsosepetawsep senses eee tb H da kn u n W KK dm sana 14 8 1 Configuration of a relay host for sending the e mails EL kk ees 14 8 2 Configuration of the maximum mail size 1 0 eee cece ce eeee ee eece KK kK kK K K K KK K KK KA 14 8 3 Configuration of a blind carbon copy for mail archiving solutions csseeeeeeeeeeeeee ne ee 14 8 4 Configuration of soft DOUNCES is E s kalk bee kk kk kak kelk d k ak dela kK k E Hae cin KUK cw e k H ek k eres 14 9 Handling of mailboxes during e mail changes and the deletion of user accounts E E E EEUU LEU 16 10 Distribution of an installation on several mail servers LLEL kk kk kK k kK k kk 17 11 Configuration of mail clients for the mail Server L h Lu kK kK K kK KH 18 12 Webmail and administration of e mail filters with Horde LLE L k 19 12 1 L gin and OVEIVIEW a H 45 x 4244y53 a3035 kre bans ca b kk b k We Kek n buk E kelk p k ca W e we je b DAD 19 12 2 Web based mail ACCESS eree sern dair dank k s n K Han k a uk alek kn sebe k dn be ku neb
6. MAP service Cyrus is also installed on the system along with the mail server component It provides e mail accounts for the domain users and offers corresponding interfaces for access via e mail clients Cyrus is preconfigured for the fetching of e mails via IMAP and POP 3 Access via POP3 can be deactivated by setting the Univention Configuration Registry variable mail cyrus pop to no The same applies to IMAP and the Univention Configuration Registry variable mail cyrus imap The further configuration of the mail server is performed via Univention Configuration Registry as well see Chapter 8 The management of the user data of the mail server e g e mail addresses or mailing list is performed via Univention Management Console and is documented in Chapter 3 User data are stored in LDAP The authentication is performed using a user s primary e mail address i e it must be entered as the user name in mail clients As soon as a primary e mail address is assigned to a user in the LDAP directory a listener module creates an IMAP mailbox on the mail home server By specifying the mail home server user e mail accounts can be distributed over several mail servers as well see Chapter 10 Optionally e mails received via Postfix can be checked for spam content and viruses before further processing by Cyrus Spam e mails are detected by the classification software SpamAssassin Chapter 4 ClamAV is used for the detection of viruses and other malware Ch
7. The Univention Configuration Registry variable mail cyrus imap quotawarnkb is used to con figure the threshold in kilobytes The quota is transferred to the quota settings of the Cyrus server during authentication on the mail server The update interval is evaluated so that the quota settings are only updated once this time period has expired This interval can be configured in minutes by Univention Configuration Registry variable mail cyrus imap quotainterval No limit values are set for the IMAP storage space in the default setting The use of mail quotas can be generally deactivated with the Univention Configuration Registry variable mail cyrus imap quota www univention de univention be open Chapter 4 Spam detection and filtering Undesirable and unsolicited e mails are designated as spam The software SpamAssassin and Postgrey inte grated in UCS for the automatic identification of these e mails SpamAssassin attempts to identify whether an e mail is desirable or not based on heuristics concerning its origin form and content Postgrey is a policy server for Postfix which implements grey listing Grey listing is a spam detection method which denies the first delivery attempt of external mail servers Mail servers of spammers most often do not perform a second delivery attempt while legitimate servers do so Integration occurs via the packages univention spamassassin and univention postgrey which are automatically set up during
8. apter 5 In the default setting e mails to external domains are delivered directly to the responsible SMTP server of that domain Its location is performed via the resolution of the MX record in the DNS Mail sending can also be taken over by the relay host e g on the Internet provider see Section 8 1 The Horde framework is available for web based mail access see Chapter 12 The UCS mail system does not offer any groupware functionality such as shared calendars or invitations to appointments However there are groupware systems based on UCS which integrate in the UCS management system such as Kolab Zarafa and Open Xchange Further information can be found in the Univention App Center www univention de univention be open Chapter 2 Installation There are two ways to install the mail server package with Cyrus instead of Dovecot e First install the application Mail server from the Univention App Center then use the UMC module Package Management to install the package univention mail cyrus e Run on the command line logged in as root univention install univention mail server univention mail cyrus A mail server can be installed on all server system roles The use of a domain controller is recommended because of frequent LDAP accesses The runtime data of the Cyrus server are stored in the var spool cyrus directory This directory should not be operated on a NFS share The webmail interface Horde can be in
9. ase keep in mind that after disabling the account or changing the password the login to the mail stack is still possible for 30min due to authentication cache of the mail stack To invalidate the authentication cache restart the saslauthd service on the mail server The expira tion time of the authentication cache can be configured with the Univention Configuration Registry variable mail saslauthd cache timeout on the mail server www univention de univention be open 3 3 Management of mailing lists Management of mailing lists Feedback C2 Mailing lists are used to exchange e mails in closed groups Each mailing list has its own e mail address If an e mail is sent to this address it is received by all the members of the mailing list Figure 3 1 Creating a mailing list Mail Project participants mailinglist General Advanced settings Basic settings General Project participants mailinglist Name All members of the project Description _projectparticipants company ex Mail address _smith company example Members _anderson company example Members _miller company example Members New entry Mail domains are managed in the UMC module Mail with the Mailing list object type A name of your choice can be entered for the mailing list under Name the entry of a Description is optional The e mail address of the mailing list should be entered as the Mail ad
10. ccessible to the user The original recipient receives a message per e mail stating that this measure has been taken If necessary the administrator can restore or delete this from the var lib amavis virusmails directory Automatic deletion is not performed The AMaViSd new software serves as an interface between the mail server and different virus scanners The free virus scanner ClamAV is included in the package and enters operation immediately after installation The signatures required for virus identification are procured and updated automatically and free of charge by the Freshclam service Alternatively or in addition other virus scanners can also be integrated in AMaViS Postfix and AMaViS need to be restarted following changes to the AMaViS or ClamAV configuration 11 www univention de univention be open Chapter 6 Identification of spam sources with DNS based Blackhole Lists DNSBL Another means of combating spam is to use a DNS based Blackhole List DNSBL or Real time Blackhole List RBL DNSBLs are lists of IP addresses that the operator believes to be potential sources of spam The lists are checked by DNS If the IP of the sending e mail server is known to the DNS server the message is rejected The IP address is checked quickly and in a comparatively resource friendly manner The check is performed before the message is accepted The extensive checking of the content with SpamAssassin and anti virus software is
11. dress The domain part of the address needs to be the same as one of the managed mail domains As many addresses as necessary can be entered under Members In contrast to mail groups see Section 3 4 external e mail addresses can also be added here The mailing list is available immediately after its creation In the default settings everyone can write to the mailing list To prevent misuse there is the possibility of restricting the circle of people who can send mails To do so the Univention Configuration Registry variable mail postfix policy listfilter on the mail server must be set to yes and Postfix restarted Users that are allowed to send e mails to the list and Groups that are allowed to send e mails to the list can be specified under Advanced settings If a field is set here only authorised users groups are allowed to send mails 3 4 Management of mail groups Feedback 2 There is the possibility of creating a mail group This is where an e mail address is assigned to a group of users E mails to this address are delivered to the primary address of each of the group members Mail groups are managed in the UMC module Groups The address of the mail group is specified in the mail address input field under Advanced settings The domain part of the address must be the same as one of the managed mail domains In the default settings everyone can write to the mail group To prevent misuse there is the possibility of restrictin
12. dules The user can personalise Horde by clicking the cog symbol 12 2 Web based mail access Feedback D Horde offers all the standard functions of an e mail client such as the sending forwarding and deletion of e mails E mails can be sorted in folders and are stored in Inbox as standard A Sent folder is created automat ically the first time an e mail is sent 19 www univention de univention be open Address book Figure 12 2 Web mail Inbox horde Zazan QUT U P DD Othersw New Message Refresh gt Forward v Other Filter v inbox 1 gg Spam Reply v f Delete Subject Date w Size Conte vitation 10 11 47 Am Happy birthday 10 13 16 2KB 8 Folder Actions w Ham Virtual Folders gt Conference invitation from lise univention test Today 10 11 47 CEST Text 1 KB iM I would like to invite you to our upcoming conference Horde differentiates between two types of deletion An e mail deleted with Delete is initially moved to the Trash folder From there it can be moved into any other folder as long as the trash can has not been emptied with Empty 12 3 Address book Feedback This module is used to administrate e mail addresses and additional contact information The information compiled here are saved in Horde s own SQL database Figure 12 3 Address book for webmail orde Groupware S16 Mail Calendar w Tasks Notes w Others w e J Ne
13. e address has to begin with a letter and must include an character At least one mail domain must be registered for to be able to assign e mail addresses see Section 3 1 A user can be assigned two different types of e mail addresses The primary e mail address is used for authentication on Postfix and Cyrus Primary e mail addresses must always be unique Only one primary e mail address can be configured for every user It also defines the user s IMAP mailbox If a mail home server is assigned to a user see Chapter 10 the IMAP inbox is automatically created by a Univention directory listener module The domain part of the e mail address must be registered in Univention Management Console see Section 3 1 e E mails to alternative e mail addresses are also delivered to the user s mailbox As many addresses can be entered as you wish The alternative e mail addresses do not have to be unique if two users have the same e mail address they both receive all the e mails which are sent to this address The domain part of the e mail address must be registered in Univention Management Console see Section 3 1 E mail addresses are managed in the UMC module Users The primary e mail address is entered in the General tab in the User account submenu Alternative e mail addresses can be entered under Advanced settings gt Mail Note Once the user account is properly configured authentication to the mail stack is possible IMAP POP3 SMTP Ple
14. e fetched mails are deleted from the server fol lowing the transfer If this option is enabled it can be suppressed 13 www univention de univention be open Configuration of a relay host for sending the e mails Chapter 8 Configuration of the mail server 8 1 Configuration of a relay host for sending the e Feedback 2 mails In the default setting Postfix creates a direct SMTP connection to the mail server responsible for the domain when an e mail is sent to a non local address This server is determined by querying the MX record in the DNS Alternatively a mail relay server can also be used i e a server which receives the mails and takes over their further sending This type of mail relay server can be provided by a superordinate corporate headquarters or the Internet provider for example To set a relay host it must be entered as a fully qualified domain name FQDN in the Univention Configuration Registry variable mail relayhost If authentication is necessary on the relay host for sending the Univention Configuration Registry variable mail relayauth must be set to yes and the etc postfix smtp_auth file edited The relay host user name and password must be saved in this file in one line FQDN Relayhost username password The command postmap etc postfix smtp_auth must then be executed for this file to adopt the changes via Postfix 8 2 Configuration of the maximum mail size Feedback The Unive
15. enerally and thus also apply for users accessing their inboxes via a standard mail client Figure 12 4 Filter management in Horde horde CESEN Mail w Calendar w Address Book Tasks w Notes w Others w 09 27 13 New Rule Existing Rules Y Filter Rules Edit Rule ee rer Whitelist 1 Spam Filter ws Yv Blackiist jli Bl 2 Marketing Fie vacation fi E 2 sas v XX To Forward B 4 Nevsletter ee ee as spam E Script Filters can be edited and expanded under Mail gt Filters The filters are applied to incoming e mails in the consecutively numbered order Their position can be altered either using the arrows to the right or by entering a number in the Move column directly Individual filter rules can be switched on and off in the Enabled column The Spam filter can be used user specifically to set which spam threshold should apply The specified Spam Level is the SpamAssassin threshold An e mail which returns this value will be sent to the specified folder A Vacation filter can be used to specify a period in which incoming e mails are automatically replied to with an answer e mail by the mail server The text and subject of the e mail can be selected as required New Rule can be used to create new rules e g for the automatic sorting of incoming mails into topic specific mail folders Clicking on Script displays the source text of the generated Sieve script 21 www univention de Bibliography ucs
16. etching emails from external POP3 or IMAP mail boxes Fetchmail can be installed via the Univention App Center simply select the Fetchmail application and then click on Install Once the installation is finished there are additional input fields in the Advanced settings gt Remote mail retrieval tab of the user administration which can be used to configure the collection of mails from an external server The mails are delivered to the inboxes of the respective users the primary e mail address must be configured for that The mail is fetched every twenty minutes once at least one e mail address is configured for mail retrieval After the initial configuration of a user Fetchmail needs to be started in the UMC module System services In that module the fetching can also be disabled alternatively by setting the Univention Configuration Registry variable fetchmail autostart to false Table 7 1 Remote mail retrieval tab Attribute Description Username The user name to be provided to the mail server for fetching mail Password The password to be used for fetching mail Protocol The mail can be fetched via the IMAP or POP3 protocols Remote mail server The name of the mail server from which the e mails are to be fetched Encrypt connection SSL TLS If this option is enabled the mail is fetched in an encrypted form when this is supported by the mail server Keep mails on the server In the default settings th
17. g the circle of people who can send mails To do so the Univention Configuration Registry variable mail postfix policy listfilter onthe mail server must be set to yes and Postfix restarted www univention de Management of shared IMAP folders univention be open Users that are allowed to send e mails to the group and Groups that are allowed to send e mails to the group can be specified under Advanced settings If a field is set here only authorised users groups are allowed to send mails 3 5 Management of shared IMAP folders Feedback Shared e mail access forms the basis for cooperation in many work groups In UCS users can easily create folders in their own mailboxes and assign permissions so that other users may read e mails in these folders or save additional e mails in them Alternatively individual IMAP folders can be shared for users or user groups This type of order is described as a shared IMAP folder Shared IMAP folders are managed in the UMC module Mail with the Mail folder IMAP object type Figure 3 2 Creating a shared IMAP folder Mail test intranet General Access Rights Basic settings Table 3 1 General tab Ae General Project IMAP folder test intranet O Name Mail domain 9 _ucs 8044 test intranet Mail home server 2048 Quota in MB _project test intranet E Mail address Attribute Name Description The name under whic
18. h the IMAP folder is available in the e mail clients Mail domain Every shared IMAP folder is assigned to a mail domain The manage ment of the domains is documented in the Section 3 1 Mail home server An IMAP folder is assigned to a mail home server Further information can be found in Chapter 10 Quota in MB E Mail address This setting can be used to set the maximum total size of all e mails in this folder An e mail address can be entered here via which e mails can be sent directly to the IMAP folder If no address is set here it is only possible to write in the folder from e mail clients The domain part of the e mail address must be registered in Univention Management Console see Section 3 1 As soon as an e mail address is entered for a folder at least the IMAP rights Lrsp are set for the user anyone so that the IMAP server can save e mails in the IMAP folder Wwww univention de univention be open Mail quota Table 3 2 Access rights tab Attribute Description Name Access permissions based on users or groups can be entered here Users are entered with their user name the groups saved in Univention Man agement Console can be used as groups The access permissions have the following consequences for individual users or members of the specified group No access No access is possible The folder is not displayed in the folder list Read The user may only perfo
19. ntion Configuration Registry variable mail messagesizelimit can be used to set the maxi mum size in bytes for incoming and outgoing e mails Postfix must be restarted after modifying the setting The preset maximum size is 10240000 bytes If the value is configured to O the limit is effectively removed Please note that e mail attachments are enlarged by approximately a third due to the base64 encoding If Horde see Chapter 12 is used the Univention Configuration Registry variables ph p limit filesize and php limit postsize must also be adjusted The maximum size in megabytes must be entered as the value in both variables Then the Apache web server has to be restarted 8 3 Configuration of a blind carbon copy for mail Feedback D archiving solutions If the Univention Configuration Registry variable mail archivefolder is set to an e mail address Post fix sends a blind carbon copy of all incoming and outgoing e mails to this address This results in an archiving of all e mails As standard the variable is not set If there is no mailbox for this address one will be created automatically Postfix must then be restarted 8 4 Configuration of soft bounces Feedback If a number of error situations e g for non existent users the result may be a mail bounce i e the mail cannot be delivered and is returned to the sender When Univention Configuration Registry variable mail 14 www univention de univention be open
20. only performed once it has been received Postfix has integrated support for DNSBLs http www postfix org postconf 5 html reject_rbl_client DNSBLs from various projects and companies are available on the Internet Please refer to the corresponding websites for further information on conditions and prices The Univention Configuration Registry variable mail postfix smtpd restrictions recipi ent SEQUENCE RULE must be set to be able to use DNSBLs with Postfix It can be used to config ure recipient restrictions via the Postfix option smtpd_recipient_restrictions see http www postfix org postconf 5 html smtpd_recipient_restrictions The sequential number is used to sort multiple rules alphanu merically which can be used to influences the ordering Tip Existing smtpd_recipient_restrictions regulations can be listed as follows ucr search brief mail postfix smtpd restrictions recipient In an unmodified Univention Corporate Server Postfix installation the DNSBL should be added to the end of the smtpd_recipient_restrictions rules For example ucr set mail postfix smtpd restrictions recipient 80 reject_rbl_client ix dnsbl manitu net 12 www univention de univention be open Chapter 7 Integration of Fetchmail for retrieving mail from external mailboxes Usually the UCS mail service accepts mails for the users of the UCS domain directly via SMTP UCS also offers optional integration of the software Fetchmail for f
21. red from processed e mails and uses this to adapt it s evaluation to the user s e mail The Bayes classification is controlled by the user himself whereby e mails not identified as spam by the system can be placed in the Spam subfolder by the user and a selection of legitimate e mails copied into the Ham subfolder This folder is evaluated daily and data which have not yet been collected or were previously classified incorrectly are collected in a shared database This evaluation is activated in the default setting and can be configured with the Univention Configuration Registry variable mail antispam learndaily The spam filtering can be deactivated by setting the Univention Configuration Registry variable mai 1 an tivir spam to no When modifying Univention Configuration Registry variables concerning spam detec tion the AMaViS service and Postfix must be restarted subsequently 10 www univention de univention be open Chapter 5 Identification of viruses and malware The UCS mail services include virus and malware detection via the univention antivir mail package which is automatically set up during the set up of the mail server package The virus scan can be deactivated with the Univention Configuration Registry variable mail antivir All incoming and outgoing e mails are scanned for viruses If the scanner recognises a virus the e mail is sent to quarantine That means that the e mail is stored on the server where it is not a
22. rm read access to existing en tries Append Existing entries may not be edited only new entries may be created Write New entries may be created in this directory existing entries may be edited or deleted Post Sending an e mail to this directory as a recipient is per mitted This function is not supported by all the clients All Encompasses all permissions of write and also allows the changing of access permissions 3 6 Mail quota Feedback 2 The size of the users mailboxes can be restricted via the mail quota When this is attained no further e mails can be accepted for the mailbox by the mail server until the user deletes old mails from her account The limit is specified by the Mail quota policy which is managed under Policies in the UMC module Users The maximum size of the mailbox of a user is specified in the Quota limit MB field The user can be warned once a specified portion of the mailbox is attained and then receives a message with every incoming mail that his available storage space is almost full This warning is shown by the e mails clients and must thus be supported by them The administrator can enter the threshold in percent or remaining diskspace in kB The threshold for when the warning message should be issued can configured in the Univention Configu ration Registry variable mail cyrus imap quotawarnpercent The value must be entered as a number between 0 and 100 without the percent sign e
23. s To this end each user is assigned a so called mail home server on which the user s mail data are stored When delivering an e mail the responsible home server is automatically determined from the LDAP directory It must be observed that global IMAP folders see Section 3 5 are assigned to a mail home server If the mail home server is changes for a user the user s mail data is not moved to the server automatically The Cyrus Murder expansion is provided for the implementation of a mailbox cluster 17 www univention de univention be open Chapter 11 Configuration of mail clients for the mail server The use of IMAP is recommended for using a mail client with the UCS mail server STARTTLS is used to switch to a TLS secured connection after an initial negotiation phase when using SMTP for sending mail and IMAP for receiving synchronising mail Password plain text should be used in combination with STARTTLS as the authentication method The method may have a different name depending on the mail client The following screenshot shows the setup of Mozilla Thunderbird as an example Figure 11 1 Setup of Mozilla Thunderbird 6 Mail Account Setup yD amp Your name Lise Meitner Email address lise univention test Password ececceccce x Remember password Configuration found by trying common server names IMAP mail univention test 143 w J STARTTLS Normal password X SMTP mail univen
24. stalled via the Univention App Center www univention de univention be open Management of mail domains Chapter 3 Management of the mail server data 3 1 Management of mail domains Feedback 2 A mail domain is an common namespace for e mail addresses mailing lists and IMAP group folders Postfix differentiates between the delivery of e mails between local and external domains Delivery to mailboxes defined in the LDAP directory is only conducted for e mail address from local domains The name of a mail domain may only be composed of lowercase letters the figures 0 9 full stops and hyphens Several mail domains can be managed with UCS The managed mail domains do not need to be the DNS domains of the server they can be selected at will The mail domains registered on a mail server are auto matically saved in the Univention Configuration Registry variable mail hosteddomains To ensure that external senders can also send e mails to members of the domain MX records must be created in the configuration of the authoritative name servers which designate the UCS server as mail server for the domain These DNS adjustments are generally performed by an Internet provider Mail domains are managed in the UMC module Mail with the Mail domain object type 3 2 Assignment of e mail addresses to users Feedback fs E mail addresses can consist of the following characters letters a z figures 0 9 dots hyphens and under scores Th
25. the installation of the mail server package SpamAssassin operates a point system which uses an increasing number of points to express a high proba bility of the e mail being spam Points are awarded according to different criteria for example keywords within the e mail or incorrect encodings In the standard configuration only mails with a size of up to 300 kilobytes are scanned this can be adjusted using the Univention Configuration Registry variable mail an tispam bodysizelimit E mails which are classified as spam because they exceed a certain number of points are not delivered to the recipient s inbox by Cyrus but rather in the Spam folder below it The filtering is performed by a Sieve script which is automatically generated when the user is created The threshold in these scripts as of which e mails are declared to be spam can be configured with the Uni vention Configuration Registry variable mail antispam requiredhits The presetting 5 generally does not need to be adjusted However depending on experience in the local environment this value can also be set lower This will however result in more e mails being incorrectly designated as spam Changes to the threshold do not apply to existing users but the users can change the value themselves in the Horde web client see Section 12 4 There is also the possibility of evaluating e mails with a Bayes classifier This compares an incoming e mail with statistical data already gathe
26. tion test vl l2s w STARTTLS Normal password lise Get a new account Advanced config Cancel Re test Done 18 www univention de univention be open Login and overview Chapter 12 Webmail and administration of e mail filters with Horde UCS integrates a number of applications from the Horde framework for web access to e mails and web based administration of server side e mail filter rules based on Sieve Horde can be installed via the Univention App Center 12 1 Login and overview Feedback 2 The Horde login mask is linked on the system overview page under Horde web client and can be opened directly at http SERVERNAME horde login php Figure 12 1 Login on Horde Username mailuser42 univention test Password 9 0 0 440 0 9 60 Mode Automatic Language English American i Login amp Either the UCS user name or the primary e mail address can be used as the user name The webmail interface can be used in a number of display modes The preferred version can be selected under Mode We recommend the use of the dynamic interface for standard workstations The remaining documentation refers to this version Selecting the Language has no effect in many web browsers as the browser s preferred language settings take precedence In the top toolbar there are a number or menu points e g Mail and Address Book which can be used to switch between the individual mo
27. w Contact Address book of bob univention test Q E Browse f Delete A Edit BY Export Add o a Contact List x Q Search A Beads v Name D imporvexport A Bo Mary Someniille BM Lise Meitner V My Address Books e E Bob Smith Address book of bob univention test gt gt Shared Address Books gt Other Address Books Contact information found using the simple or advanced search can then be copied into individual address books and edited there New contacts can be entered via the New Contact menu item Personal address books can also be created via My Address Books The Browse menu item can be used to display the contents of address books The lists can be sorted alpha betically by clicking on the preferred column title surname first name etc Clicking on the magnifying glass in the header of the respective address book directly next to the name of the address book opens a search field that can be used easily to search within the open address book Individual addresses in a list can be marked with an X for subsequent use i e to export them as a file in a certain file format or to copy them into another address book 20 www univention de univention be open E mail filters 12 4 E mail filters Feedback 9 Cyrus supports server side filter scripts written in an individual script language called Sieve The filter module allows the generation of these filter scripts They apply g
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