[manthrax3]

I like using 587 for SMTP submission because it is rarely blocked by firewalls while 25 is almost always blocked.

To enable this in Zimbra, I uncommented the following lines in ~zimbra/postfix/conf/master.cf:

submission inet n - n - - smtpd
-o smtpd_etrn_restrictions=reject
-o smtpd_enforce_tls=yes -o smtpd_sasl_auth_enable=yes

The run:

postfix reload

Works great. This should probably be the default behavior.

bp