MX record in zone file

[Guy Fraser]

On Thu, 2005-13-01 at 13:19 +0100, Alexander Dalloz wrote:
> Am Do, den 13.01.2005 schrieb Rudolf Amirjanyan um 20:56:
> 
> > In DNS records, I.E zone file, is it possible to write IP address of the
> > mail server instead of host domain name?
> > like:
> > 
> > DOMAIN.COM in mx 10 123.123.123.123.
> 
> > Rudolf
> 
> As Paul and Grep said: don't do that.
> And btw. an IP is never followed by a trailing dot, only hostnames.
> 
Only when an IP is expected.

In this case a host name is expected and puting an IP without 
the period at the end would result in the domain being appended 
to the IP address.

As everyone has said "Just say NO to IPs in MX records."

Another point that needs to be made:

If you intend on having this mail server publicly accessible 
you should also ensure that the reverse is set to the same 
name as the a record for your mail server. Failure to adhere 
to this will cause many mail servers to reject mail from 
you. Also make darn sure that you only allow your local 
machines to relay mail through that machine.

...snip