I have suse-9.2 system being used to educate people about email. We use kmail
for this and they can only send email to the people on the suse machine. The
machine has the name (let's say) mickei.
No when I set the reply-to address in kmail to 'roes@mickei' this is altered
by the post system to 'roes@domain.test' (where domain.test is an example,
but it illustrates the fqdn of the machine).
In the kmail's outbox the message header looks as:
From: Nobody