we have a multiserver-installation of Zimbra 8.0.4. Ubuntu_64 Network Edition. (MailTransferAgent and Mailbox).
We want to implement the "rbl-whitelisting", ollowing these instructions:
In these instructions I have to execute the "postmap-command": "postmap /opt/zimbra/conf/postfix_rbl_override"
But i have no postmap on this system. And if I want to install the "postfix", Ubuntu will remove my zimbra-installation.

Can anybody help me, how to implement this command?