Whitelist IP addresses when using RBL

Ref: http://wiki.zimbra.com/wiki/Improving_Anti-spam_system#Postfix_whitelist_when_using_RBL.27s

As root, edit /opt/zimbra/conf/postfix_recipient_restrictions.cf, under reject_unauth_destination, add check_client_access hash:/opt/zimbra/conf/postfix_rbl_override, like:

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

Then:

su - zimbra -c 'zmmtactl restart'

Run as user zimbra, add address to /opt/zimbra/conf/postfix_rbl_override:

su - zimbra
cd /opt/zimbra/conf/

nano postfix_rbl_override

postmap hash:postfix_rbl_override