If you are like me and you want to restrict based access to distribution list based on IP address, here are the minor mods to make it work rather then using the from address of the sender.
Start at the WIKI and get that example working
http://wiki.zimbra.com/index.php?tit...tfixRecipients
Once you realize it has the problem of email address spoofing you can implement the IP restriction access instead.
The only changes necessary are to change a line added to /etc/zimbra/postfix/conf/main.cf, the permitted_senders_list, change it to the type of check_client_access rather then check_sender_access. Then in your permitted_senders file add a line for each IP you wish to allow access to the distribution list.
192.168.1.20 OK
192.168.3.20 OK
I didn't try a cidr: type table but it would probably work fine with a check_client_access macro.