Postfix definition question.
 

Hello.

In the following command where it says .$mydomain what does this literally mean?

Does it mean to use this spelling exactly as is or does this mean to insert your own domain name such as XYZ.

postconf -e 'myhostname = server1.$mydomain'

Thanks

It means type that exactly. The variable $mydomain should be defined correctly in your /etc/postfix/master.cf file; when you tell postconf to execute the line 'myhostname = server1.$mydomain', it will set the variable $myhostname to the DNS name server1.{whatever is in $mydomain}.

Thanks all this now makes sense.