Question about MX record

[Kevin Darcy]

RFC 1035:



> 3.3.9. MX RDATA format
>
>     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
>     |                  PREFERENCE                   |
>     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
>     /                   EXCHANGE                    /
>     /                                               /
>     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
>
> where:
>
> PREFERENCE      A 16 bit integer which specifies the preference given to
>                 this RR among others at the same owner.  Lower values
>                 are preferred.
>
> EXCHANGE        A <domain-name> which specifies a host willing to act as
>                 a mail exchange for the owner name.
>

- Kevin


Klinkefus, David S wrote:

> Greetings!
> I had a request for any RFC, or reference material, that says
> that a zone MX record must point at a host record instead of an IP address.
> We discovered a zone that had just the IP address in the MX record,
> and we couldn't do a forward lookup on that IP address to trade e-mail.
> Our firewall sendmail process saw the IP address as a sub-domain name
> because
> of the dots in the address.