[SHAME] Spam Rats

Tony Finch dot at dotat.at
Fri Jan 11 12:32:30 UTC 2013

John Levine <johnl at iecc.com> wrote:

> >*. 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

f.anthony.n.finch  <dot at 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.

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