Hi guys,

my first post.

The problem I am experiencing is that I received quite a lot of SPAM from the domain pretending to be my own.

so if the email is user@example.com, this account receives the email from administrator@example.com

is there any way to make sure that all the email coming from example.com domains would have to be authenticated.

In exim, the MTA I've moved to zimbra from, it was rather simple

# Deny from local domains if sender is not authenticated
deny sender_domains = example.com
!authenticated = *
message = Please authenticate in order to send mail from your domain

is there similar functionality in zimbra/postfix?