At the end of it, I ran some checks, and it seems that the server is an open relay.
I tested this using the following online checks:
I also tested using the "sendemail" script from a different ubuntu box.
Code: Select all
sendemail -f "firstname.lastname@example.org" -t "emailaddress@someotherdomain" -u "relay test" -s "mydomain.com"
This happily sent an email to "emailaddress@someotherdomain", from the non existent email on my domain.
I read in the documentation that zimbra's postfix is supposed to have open relaying turned off by default.
Have I turned it on by mistake? How do I turn it off?