John Levine <jo...@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 <d...@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.