How to restrict outgoing email as well as external web access for certain users?
Restricting users to send mails to certain domains
1. Enter following in the file “/opt/zimbra/conf/postfix_recipient_restrictions.cf”. Make sure it is entered at the top of the file.
ZCS 8.x: Enter in file /opt/zimbra/conf/zmconfigd/smtpd_recipient_restrictions.cf
vi /opt/zimbra/conf/postfix_recipient_restrictions.cf check_sender_access hash:/opt/zimbra/postfix/conf/restricted_senders
Note: This line should be added after the reject_non_fqdn_recipient line
Note: ZCS 8.5 and later use lmdb databases, not hash databases
2. Enter following in “/opt/zimbra/conf/zmmta.cf”
ZCS 8.x: Enter in file /opt/zimbra/conf/zmconfigd.cf
vi /opt/zimbra/conf/zmmta.cf Find the section labeled SECTION mta and enter the following two lines directly below POSTCONF smtpd_restriction_classes local_only POSTCONF local_only FILE postfix_check_recipient_access.cf
3. Create a file “/opt/zimbra/conf/postfix_check_recipient_access.cf”
vi /opt/zimbra/conf/postfix_check_recipient_access.cf check_recipient_access hash:/opt/zimbra/postfix/conf/local_domains, reject
4. Create a file “/opt/zimbra/postfix/conf/restricted_senders” and list all the users, whom you want to restrict. Follow this syntax:
vi /opt/zimbra/postfix/conf/restricted_senders firstname.lastname@example.org local_only
5. Create a file “/opt/zimbra/postfix/conf/local_domains” and list all the domains where “restricted users” allowed to sent mails. Please follow this syntax:
vi /opt/zimbra/postfix/conf/local_domains yourdomain.com OK otheralloweddomain.com OK
6. Run following commands:
postmap /opt/zimbra/postfix/conf/restricted_senders postmap /opt/zimbra/postfix/conf/local_domains zmmtactl stop zmmtactl start
After these settings, all the users listed in “/opt/zimbra/postfix/conf/restricted_senders” are restricted to send mails only to domain which are defined in “/opt/zimbra/postfix/conf/local_domains”, other are fully allowed to send mails anywhere. These settings will not survive Zimbra upgrades, please make sure that you backup of all these settings while performing upgrades.