relay_recipient_maps in zimbra

[prasadpimple]

Hi

i am using zimbta with domian name abc.com & i want to configured the smtp authetication along with trusted recipient address , so authetic only my domain users will able to relay the mail to external domain
currently i had enebaled the smtp authetication but i have doubt on some culprit users who are sharing there username & password with other
and they are suing my smtp with given authetication information for relaying their mail
i had gone through various document & found that there is wat to block this using postfix elay_recipient_maps config so that only specified domain users recipient user on configuration will able to send the mail even though the users are autheticate on my MTA

please help me here how to config relay_recipient_maps in zimbra

Prasad

[prasadpimple]

any body who is postfix expert can help me here