I tried the 2nd and 3rd option during my troubleshooting before my post, reloaded the configuration and even bounced the service without anything changing. The first option does not have the domain included and I am leery of changing an OS file like /etc/hostname for fear of some application breaking after the change.
-----Original Message----- From: owner-postfix-us...@postfix.org <owner-postfix-us...@postfix.org> On Behalf Of Wietse Venema Sent: Tuesday, September 27, 2022 2:24 PM To: postfix-users@postfix.org Subject: Re: Wrong Domain in Null Client Setup Viktor Dukhovni: The options are: - Set a FQDN in /etc/hostname (or equivalent) - Set a FQDN in main.cf:myhostname - Set main.cf:mydomain Postfix will not rely on DNS to figure out its domain name, because it must be able to run when the network is down. Wietse Wietse Postfix must be able to run on a disconnected machine, and therefore it cannot use DNS to figure out the domain portion of Wietse