unwise filtering policy from cox.net

Eliot Lear lear at cisco.com
Wed Nov 21 12:16:02 UTC 2007

Hey Paul,

> -- Sean Donelan <sean at donelan.com> wrote:
> > On Tue, 20 Nov 2007, goemon at anime.net wrote:
> >> <abuse at cox.net>
> >>    (reason: 552 5.2.0 F77u1Y00B2ccxfT0000000 Message Refused.  A
> URL in
> >> the content of your message was found on...uribl.com.  For
> resolution do
> >>  not contact Cox Communications, contact the block list
> administrators.)
> > An unfortunate limitation of the SMTP protocol is it initially only
> > looks at the right-hand side of an address when connecting to a
> > server to send e-mail, and not the left-hand side.  [...]
> Sure, it's an "unfortunate limitation", but I hardly think it's
> an issue to hand-wave about and say "oh, well".
> Suggestions?

Given what Sean wrote goes to the core of how mail is routed, you'd
pretty much need to overhaul how MX records work to get around this one,
or perhaps go back to try to resurrect something like a DNS MB record,
but that presumes that the problem can't easily be solved in other
ways.  Sean demonstrated one such way (move the high volume stuff to its
own domain).


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