John R. Levine <johnl(_at_)iecc(_dot_)com> wrote:
DNSBLs already set the min pretty low, e.g. 150 sec for Spamhaus. Doesn't
really matter how low it is if you have so many entries that they force out
the useful ones.
The really important records are the delegation chain NS records. It is
not so necessary to keep leaf records in the cache.
http://nms.csail.mit.edu/projects/dns/
Modern spam filters don't usually look up the author domain, since it's
usually a genuine address taken from the spam list so it's unrelated to the
real sender.
I think it's still useful to reject mail with an unresolvable return path
domain.
Tony.
--
f.anthony.n.finch <dot(_at_)dotat(_dot_)at> http://dotat.at/
Lundy, Fastnet: Southwest 4 or 5, increasing 6 or 7 later. Moderate or rough,
occasionally very rough later in Fastnet. Showers. Good.
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