Hello,
I have here two different postfix installations, one is postfix
2.11.3-1
from Debian 8, the other is postfix 3.1.0-3 from Ubuntu 16.04.
/etc/postfix/
main.cf is the same on both machines, mydomain and myhostname are not
set
in main.cf . When I call postconf, I get
mydomain = cs.uni-dortmund.de
myhostname = cloudhost177.cs.uni-dortmund.de
on the Debian machine, but
mydomain = localdomain
myhostname = cloudhost176.localdomain
on the Ubuntu machine.
From http://www.postfix.org/postconf.5.html#myhostname: the default
[for
myhostname] is to use the fully-qualified domain name (FQDN) from
gethostname(), or to use the non-FQDN result from gethostname() and
append
".$mydomain"
- i.e. what you see when you type 'hostname' at the command line, which
in
turn is usually taken from the contents of /etc/hostname. And mydomain
is
by default derived from myhostname. If you update /etc/hostname you may
also need to update /etc/hosts.
The format of /etc/hostname and /etc/hosts is exactly the same on the
two machines, only the actual values differ. /etc/hostname contains the
non-FQDN name, /etc/hosts contains first the FQDN and then the non-FQDN.
Regards
Christoph
