Open relay? Nonlocal recips but not originating: ...

[Jim Rice]

Greetings,

I recently upgraded to Zimbra 6.0.10 which now includes amavisd-new 2.6.4
(This has already been posted to the Zimbra forums as well.)

Following the upgrade, I noticed lots of these errors being logged:

Mar 11 11:48:39 mymail amavis[16435]: (16435-17) Open relay? Nonlocal recips but not originating: user at somewhere.net

I get one for each outbound message from clients within our network.
Most of the Zimbra configuration works out of the box using defaults.

But one difference I found in the new version is this feature:

$policy_bank{'MYNETS'} = {
  originating                 => 1,
  allow_disclaimers           => 0,
  log_level                   => 1,
};

I am not sure what I need to do to eliminate these warnings.
I have tested our server with the Open Relay test sites, and we are OK.
This traffic is legitimate outbound email from trusted clients.
Postfix is configured for mynetworks = ...
But I need to tell amavis that somehow.

Can someone point me in the right direction?

Thanks,
Jim