Steven Champeon wrote:
on Thu, Jan 13, 2005 at 10:25:18AM +0530, Suresh Ramasubramanian wrote:
On Wed, 12 Jan 2005 23:19:47 -0500, Valdis.Kletnieks@vt.edu <Valdis.Kletnieks@vt.edu> wrote:
On Wed, 12 Jan 2005 19:19:24 PST, Dave Crocker said:
In general, that's what dkeys/iim and csv (and maybe spf) are attempting to provide.
Yes, but he asked for a rDNS solution specifically...
I think Steve was referring to some things that can be implemented right away, like "if you operate a mailserver, please make sure that it isn't on a host that has reverse dns like ppp-XXX.adsl.example.com, try to give it unique and non generic rDNS, preferably with a hostname that starts off with smtp-out, mail, mta etc)"
Yep. And it helps if the rDNS is "right-anchored", (uses "subdomains" to distinguish between various assignment types and technologies) a la
1-2-3-4.dialup.dyn.example.net ^^^^^^^^^^^^^^^^ 4-3-2-1.dsl.static.example.net ^^^^^^^^^^^^^^^^^^^ as opposed to
dyn-dialup-1-2-3-4.example.net static-dsl-4-3-2-1.example.net
as the former is easier to block using even the simplest of antispam heuristics. I'd love to see a convention, or even a standard, arise for rDNS naming of legit mail servers. But I'll happily settle for decent and consistent rDNS naming of everything else ;)
What is wrong with MTAMARK? MTAMARK tags the reverse entries of IP addresses where SMTP servers are. Fixes this problem very fast, efficient and with little effort (script magic to regenerate the reverse DNS entries). ftp://ftp.rfc-editor.org/in-notes/internet-drafts/draft-stumpf-dns-mtamark-03.txt -- Andre