[ale] First time setting up mail server (postfix & dovecat)

[Jeremy T. Bouse]

First off, just a little semantics but it [mail.example.com] is a 
HOSTNAME not a SUBDOMAIN.

Now, on the meat of the question...

The 'myhostname' is just that, it's the host's hostname and what 
Postfix will use when it adds it's 'Received' headers to any mail 
messages whether inbound or outbound. It does not really affect the 
operations of Postfix.

The 'mydomain' is specifying the domain which is used in several other 
areas of the Postfix config where it appends $mydomain to values. This 
is also used to append to addresses that are not fully-qualified and 
just contain the username or a short hostname without a fully-qualified 
domain name.

Neither 'myhostname' or 'mydomain' have any bearing on Dovecot, well, 
as they are Postfix configurations so telneting to the IMAP port 
(143/tcp) which Dovecot is listening won't display any problems with the 
Postfix configuration. To check Postfix you'd want to check the SMTP 
port (25/tcp) or Submission (587/tcp) but that would require using the 
openssl s_client connection to support STARTTLS.

On 17.12.2013 11:02, Adrya Stembridge wrote:
> Im attempting to set up my trac installation to accept replies via
> email.   This is the first time configuring a machine to receive
> mail, and I have a noobish question.   
>
> In postfix/main.conf I am asked to provide "myhostname", which the
> examples show as mail.example.com [1].   The next config item is
> "mydomain", which the examples show as example.com [2]. 
>
> I dont expect much inbound mail traffic.   Is it necessary to have a
> subdomain for mail to be received?  If not, is there any gotchas with
> having identical values for "myhostname" and "mydomain"?
>
> PS: Im actually able to establish a connection to my server both
> locally and remote using "telnet example.com [3] 143" even though my
> "myhostname" value is mail.example.com [4].   The connection fails
> with "telnet mail.example.com [5] 143" since that subdomain is not
> configured in DNS.  
>
> Thanks.
>
> Links:
> ------
> [1] http://mail.example.com
> [2] http://example.com
> [3] http://example.com
> [4] http://mail.example.com
> [5] http://mail.example.com