On Thu, Apr 28, 2022 at 12:02:50PM -0500, David Wright wrote: > $ cat /etc/mailname > acer.corp1 > $ cat /etc/hosts > 127.0.0.1 localhost > 127.0.1.1 acer1.corp acer1 > 192.168.1.14 axis.corp axis > > # The following lines are desirable for IPv6 capable hosts > ::1 localhost ip6-localhost ip6-loopback > ff02::1 ip6-allnodes > ff02::2 ip6-allrouters > $ hostname > acer
But you no longer have 'acer' in your /etc/hosts file. Your hostname therefore won't have *any* canonical form with dots in it. > $ domainname > (none) That's an NIS command. It's used by NIS only. It has nothing to do with what you appear to think a "domain name" is. > and here's the email on axis: > > >From [email protected] Thu Apr 28 11:37:06 2022 > Return-path: <[email protected]> > Envelope-to: auser@axis > Delivery-date: Thu, 28 Apr 2022 11:37:06 -0500 > Received: from [192.168.1.10] (helo=acer) > by axis.corp with esmtp (Exim 4.92) > (envelope-from <[email protected]>) > id 1nk78c-0001yL-Bm > for auser@axis; Thu, 28 Apr 2022 11:37:06 -0500 > Received: from auser by acer with local (Exim 4.94.2) > (envelope-from <auser@acer>) > id 1nk78b-0000HX-6v > for auser@axis; Thu, 28 Apr 2022 11:37:05 -0500 Here, you can see that there was no canonical expansion of "acer" into a dot-laden name, so your system only identified itself as "acer". Not as "acer.corp" or anything similar, in its HELO. If one of the entries in your /etc/hosts file had contained "acer" as an alias, then the outcome would have been different. Interestingly, acer.corp *does* appear in the envelope sender address, which you can see in the "From " line and the "Return-path:" header. But in the bottom Received: header, it says "envelope-from <auser@acer>". I find that quite interesting, but you'd need more knowledge of exim configuration than I possess to work out what happened there.
