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Re: Multiple host names for a single server?

On Mon, Jan 07, 2019 at 10:13:03AM -0600, Tom Browder wrote:
> I would like to use a single server for multiple remote services
> including mail, bind dns, OpenStreep tiles, etcs., all with different
> subdomain names but sharing the same server and IP.  For example:
>   mail.example.com
>   ns1.example.com
>   tiles.example.com
>   ...
> I know I can define them with individual A records (with the same IP)
> with my domain host provider, but will that cause problems conflicting
> with a single physical hostname of, say, "pluto.example2.net"?
> In other words, is the physical hostname of any server of any
> importance except for logged in users?

The actual hostname as set in /etc/hostname does not have to match any
of the various DNS A records, although it will save you some Sanity
points if it does.

The primary purpose of the actual hostname is for you to be able to
identify *which* computer is having a problem.  E.g. if you receive an
email from a machine identifying itself as "www.yourdomain" but you have
three such web servers operating as a round robin, then you will have
to put in some work to figure out which of the three it came from.

But if the email comes from a machine which self-identifies as
"www1.yourdomain", then you have a better idea where to fix the issue.