nanog mailing list archives

Re: [SHAME] Spam Rats


From: Tony Finch <dot () dotat at>
Date: Fri, 11 Jan 2013 12:32:30 +0000

John Levine <johnl () iecc com> wrote:

*.4.4.3.0.5.a.0.0.8.b.d.0.1.0.0.2.ip6.arpa. PTR a.node.on.vlan344.namn.se.
...will work just fine, for instance.

Since there is no AAAA record for a.node.on.vlan344.namn.se., this
won't work fine in any rDNS check I'm aware of.

I believe it's relatively common for mail servers to just check the
existence of a PTR record without any further sanity checking, e.g.
Postfix's reject_unknown_reverse_client_hostname smtpd_client_restrictions
option.

Tony.
-- 
f.anthony.n.finch  <dot () dotat at>  http://dotat.at/
Forties, Cromarty: East, veering southeast, 4 or 5, occasionally 6 at first.
Rough, becoming slight or moderate. Showers, rain at first. Moderate or good,
occasionally poor at first.


Current thread: