Re: DNS goofups galore...

From: Kai Henningsen (
Date: Mon Feb 12 2001 - 15:20:00 EST (Henning P. Schmiedehausen) wrote on 12.02.01 in <968mjv$l9t$>:

> (Jan Gyselinck) writes:
> >There's not really something wrong with MX's pointing to CNAME's. It's
> >just that some mailservers could (can?) not handle this. So if you want to
> >be able to receive mail from all kinds of mailservers, don't use CNAME's
> >for MX's.
> No. It breaks a basic assumption set in stone in RFC821. It has
> nothing to do with mailer software.

May I point out that RFC 821 does not mention either CNAME or MX anywhere.

The successor (which is currently finished and waiting for publication as
RFC 2821) mentions both, but does not say if MX->CNAME is allowed or
forbidden. (And it says it's tightened up from RFC 974.)

Incidentally, it's also silent on the name vs. address MX question.
Looking at 974 and RFCs referenced from there might help to find
ammunition. But note that this is significantly later than 821.

So don't tell us about stuff set in stone in RFC XYZ, when it's plain
you've never looked at that RFC.

MfG Kai
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This archive was generated by hypermail 2b29 : Thu Feb 15 2001 - 21:00:19 EST