MX loops back to self error?

[Mathias Körber]

> I am trying to set up a small local domain with one server handling =
DNS
> and mail.  When I try to set MX to a name that has the same IP as the =
DNS
> server, I sometimes get errors:
>=20
>  ----- Transcript of session follow -----
> 553 mail.linux.bogus. config error: mail loops back to me (MX =
problem?)
> 554 root at linux.bogus... Local configuration error

This is not a DNS error, but a mailer error. You are telling the world
to send mail for other names to this machine, but you have not told
the machine to consider itself those other names.

You do that by adding the additional names to /etc/sendmail.cw
(or equivalent), so that sendmail knows to accept mail for those names
as local, rather than trying to send them on and then finding that =
itself
is the final destination according to the DNS.

regards