North American Network Operators Group
Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: unwise filtering policy from cox.net

  • From: Eliot Lear
  • Date: Wed Nov 21 07:21:27 2007
  • Authentication-results: ams-dkim-1; [email protected]; dkim=pass (s ig from cisco.com/amsdkim1002 verified; );
  • Dkim-signature: v=0.5; a=rsa-sha256; q=dns/txt; l=1105; t=1195647372; x=1196511372; c=relaxed/simple; s=amsdkim1002; h=Content-Type:From:Subject:Content-Transfer-Encoding:MIME-Version; d=cisco.com; [email protected]; z=From:=20Eliot=20Lear=20<[email protected]> |Subject:=20Re=3A=20unwise=20filtering=20policy=20from=20cox.net |Sender:=20; bh=SnyZjJZzR1wyW5jQptdSfFl93QdRdmXNjl6HWygStvw=; b=iot1AmYgShBveTJ8wK1qUgHtQi6ZnIl4J2sBk3N3h4rBA3/wivIYdP8yZfGxk2p64LfJBjUk lSZFcC4f/UlZjlDkZBfIvdaIJ4bW5Fygdx3FPpr9asKqFyFbH4cpBidH;
Hey Paul,

> -- Sean Donelan <[email protected]> wrote:
>
> > On Tue, 20 Nov 2007, [email protected] wrote:
> >> <[email protected]>
> >>    (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).

Eliot