RE: [cobalt-users] MX record question / Raq4i

[SM <nntp@xxxxxxxxx>]

Hi,
At 11:54 19-12-2001 -0500, Chris Demain wrote:
>Right, got that part.  My question, I suppose, is why MX each host instead
>of a "blanket" MX for the domain.  The only sane reason I can think of for
>having MX for each host/subdomain is for when different mail swervers are
>used, i.e. domain goes to mail., but www. goes to mail2.

You may have seen Cobalt boxes sending out emails as user@xxxxxxxxxxxxxx
for example.  If you have a MX record for each hostname for which you
accept mail, then the @www.domain.com email adheres to the specifications.

RFCs helps to ensure that different computers, no matter which hardware or
software they run, can "talk" to each other when implemented.  RFCs also
help to ensure reliability and scalability.  The MX RR was introduced so
that you can run mail services on a different server which can be on an
entirely different domain.

RFC 974 covers mail routing.  There are also some other RFCs which explains
DNS implementation and administration as well as mailbox names to be used.
If I want to contact the administrator about an email from @www.domain.com,
for example, I would email postmaster@xxxxxxxxxxxxxxx  If domain.com were
to use a "blanket" MX for the domain, then the MX lookup would fail when my
mail server sends that email.

Regards,
-sm