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Re: RFC 2?821 and CNAMEs

martin f krafft <madduck@debian.org> writes:

> I can't believe DNS (or SMTP for that matter) hasn't moved along in
> decades... at least not since people started to understand that data
> redundancy (not caching!) is a bad thing.

Yeah, both DNS and SMTP basically froze in stone a while back, and except
for the stuff that can be done with new RRs in DNS or extensions in SMTP,
really nothing changes.  Too much code out there that will break if any
little thing is different.  There are advantages to having a mature
standard, but it means that we get to live with all the mistakes and
marginal decisions forever and one ends up just memorizing them.

This is particularly bad in the area of SMTP because it's hard enough to
write a fully compliant to every last detail SMTP agent that it's a great
way of catching spamware, which is often written by incompetent
programmers or in a huge hurry.  So it's become quite popular to enforce
every little detail of the SMTP standard, no matter how obscure, because
the main Unix MTAs follow the standard in great detail and every new thing
that you can find rejects a bunch of spam.

For example, Stanford University rejects 80% (!!) of our incoming mail
just by requiring an RFC-2821-compliant HELO.

> Sorry for the noise on d-devel.

It's a little off-topic, but it's obscure enough stuff that affects enough
people that I think it's nice to repeat it periodically.  I end up
answering a ton of questions like this in my day job.

Russ Allbery (rra@debian.org)               <http://www.eyrie.org/~eagle/>

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