Viktor Steinmann wrote:
> On 04.01.2017 08:54, Per Jessen wrote:
>> Is there any point in greylisting genuine mailservers? We only
>> greylist dodgy-looking setups.
> I don't see how this approach would scale.
To my knowledge, it scales quite well. We maintain a list of regex
server-name patterns that we consider 'dodgy' as well as a whitelist.
If a reverse lookup matches one of these patterns, we greylist. There
are some more checks, e.g. on the HELO, but the reverse mapping is the
main one. We run this on a cluster of some 45-46 boxes. The list of
patterns is fairly stable.
Per Jessen, Zürich (1.9°C)
http://www.dns24.ch/ - your free DNS host, made in Switzerland.
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