FQDN's and mail MX's

[Ray Bush]

Jim Reid wrote:

> >>>>> "Ray" == Ray Bush <rbush at scryptography.com> writes:
>
>     Ray> Please help us settle a bit of an arguement here.  Should (as
>     Ray> in does it need to be) mail mx's be fully qualified domain
>     Ray> names?
>
> Didn't you try reading RFC1034? I quote:
>
>                 MX              a 16 bit preference value (lower is
>                                 better) followed by a host name willing
>                                 to act as a mail exchange for the owner
>                                 domain.
>
> To the RDATA part of an MX record should have a hostname after the
> preference value. That hostname needs to have an A record somewhere
> else in the zone file (or in somebody else's zone file if it belongs\

So there is no matching  PTR record need?  Is there a chance of problems
when there is no such matching PTR record?  If so what kinds of problems may
occur? If say there is a PTR record but it maps to a different name (that
does have an A record).

>
> to a different domain). To avoid mistakes, I'd recommend that the
> hostname is entered as a fully-qualified domain name (FQDN), explictly
> terminated with a dot. If this isn't done, the name server will append
> its idea of the current domain name - the domain origin - to get a FQDN.

Perhaps FQDN is not the right term as i do not consider a name to be in that
category when the forward A record does not match the PTR record.  Am i
incorrect in my usage?  Is there a particular name for addresses that match
forward and reverse?