because this thread started on port-vax i'm cc'ing it.  i'd like it to end now,
and to that end i will not be responding to more mail on this topic unless it
appears on the namedroppers list where it belongs.  private mail won't work,
and port-vax mail won't work.  someone asked, in private e-mail:

> Remind me, is the MX pointing to a CNAME wrong because it is somehow evil,
> or is it just because it isn't in the RFC?

because the rfc says it can't happen, clients of an MX response are not
required to cope with the case where the MX target isn't of an A RR.  there
are two valid forms of an MX response:

	ans:	mailer		IN MX	priority server
	add:	server		IN A	address

and...

	ans:	mailer		IN MX	priority server

that is, maybe there will be additional data, and maybe there won't be.  i
know of mailers who, though wholly conformant to the rfc's in this area, and
able to process both of the above forms, cannot cope with either:

	ans:	mailer		IN CNAME alias
		alias		IN MX	priority server
	add:	server		IN A	address

or...

	ans:	mailer		IN CNAME alias
		alias		IN MX	priority server

"cannot cope" means they (properly) skip over all RR types that they aren't
looking for.  "cannot cope" means they can't deliver mail to domains that are
named this way, and further, that the error message they send back to their
users is not indicative of the problem, it's just a general "you didn't get
what you want, and i don't know the reason" message.

if the rfc's required this, then i would be trying to get the MX consumers
changed.  but the rfc's don't require it, in fact the rfc's explicitly say
that it can't happen, so i'm trying to get the MX servers changed.

it's not religion, it's operations.