Hi there
a customer of mine is using Nokia with Zimbra; the only issue is that Nokia use an adressess pool to handle imap & smtp.

As you can see here:

2010-03-11 08:24:43,455 INFO  [ImapServer-5746] [name=xxxx@cost.it;ip=;] imap - user xxxxx@cost.it authenticated, mechanism=PLAIN
2010-03-11 08:31:34,921 INFO  [ImapServer-5749] [name=xxxxx@cost.it;ip=;] imap - user xxxx@cost.it authenticated, mechanism=PLAIN
xxxxx was authenticated with ip then;

at 2010-03-11 08:31:34 he sent out an email:

Mar 11 08:31:34 webmail postfix/smtpd[18153]: NOQUEUE: reject: RCPT from unknown[]: 554 5.7.1 <xxxxxx@xxxxx.it>: Relay access denied; from=<xxxxxx@cost.it> to=<xxxxx@xxxxxx.it> proto=ESMTP helo=<vienec6mg02>
with ip, and get back in his face 554, Relay access denied

what can be done to get rid of this issue?