White list for ZIMBRA to bypass RBLs

If you use RBLs such as spamhaus.org on ZIMBRA to block spam, you may sometimes find that a customer’s mail server has been blacklisted by the RBLs and cannot send to your system. It has been identified as a potential spam source and added to the blacklist. To allow blacklisted customers to continue sending email to your system, follow these steps:

1. Create /opt/zimbra/conf/postfix_rbl_override with this command: vi /opt/zimbra/conf/postfix_rbl_override In the file, enter the mail server’s IP address or mail server name, followed by “OK”, as in this example:

   1.2.3.4                   OK
   หรือ
   mail.ezymailhosting.com   OK

   Reading note: the Thai word between the two entries means “or”; the entries show alternative formats.

2. Run postmap to create the hash file used by postfix: postmap /opt/zimbra/conf/postfix_rbl_override

3. Edit /opt/zimbra/conf/postfix_recipient_restrictions.cf for ZIMBRA 7, or /opt/zimbra/conf/zmconfigd/smtpd_recipient_restrictions.cf for ZIMBRA 8. ZIMBRA 7 vi /opt/zimbra/conf/postfix_recipient_restrictions.cf ZIMBRA 8 vi /opt/zimbra/conf/zmconfigd/smtpd_recipient_restrictions.cf Below reject_unauth_destination add check_client_access hash:/opt/zimbra/conf/postfix_rbl_override For example:

   permit_mynetworks
   reject_unauth_destination
   check_client_access hash:/opt/zimbra/conf/postfix_rbl_override
   reject_unlisted_recipient

4. Restart the MTA server with this command: zmmtactl restart