When I run a test on my mail server using a tool such as dnsqueries.com....I get the message:
The SMTP server does not accept mails to postmaster@[IP_ADDRESS]. This is a very bad thing, as this address is used by people that don't know your domain name! The reported error is:
501 5.1.3 Bad recipient address syntax
I tried to configure this but Zimbra doesn't seem to allow this...at least with my default configuration. Is there a way to configure this? It seems to be a requirement for mail servers.