----- Original Message -----
From: "Petr Novotny" <[EMAIL PROTECTED]>
> On 12 Sep 2000, at 16:32, Michael T. Babcock wrote:
>
> > cf. http://www.faqs.org/rfcs/rfc974.html
> >
> > This is the only mention of the non-use of CNAMEs in the mail
> > standards.
>
> I beg to differ. Please have a look at RFC1912, called "Common
> DNS errors". Quoting section 2.4:
> > [RFC 1034] in section 3.6.2 says this should not be done, and [RFC
> > 974] explicitly states that MX records shall not point to an alias
> > defined by a CNAME. This results in unnecessary indirection in
> > accessing the data, and DNS resolvers and servers need to work more
> > to get the answer. If you really want to do this, you can
> > accomplish the same thing by using a preprocessor such as m4 on
> > your host files.
RFC1912 is "Category: Informational" and is a recommendation, not an
Internet standard (that was my original point). RFC 1034 is also a
non-standard recommendation (only) from 1987 and I'm unable to open RFC 974
for perusal right now.
Please note the difference ... RFCs are good reading. HTTP and several
other non-standard protocols are entirely implemented based on RFCs, but are
allowed to diverge from those RFCs without anyone having the right to be
terribly upset because they are /not/ Internet standards. It is sometimes a
good idea to follow the recommendations in non-standards RFCs. In many
cases, citing 'its in an RFC' is irrelevant though, as the carrier pigeon
implementation of IP should demonstrate.
