Re: [Dovecot] Unoffical Survey - What MTA/Spam filtering do you use?

Simon Waters wrote:

Would love to see so serious analysis of "HELO" based blocking. Whilst I tend to think it is a bad idea, if there are criteria I can exploit in identifying things that aren't genuine mail servers -- it fits the strategy.

Some very broken spam tool sends IP address of an MX host it is speaking to in HELO response, this should never happen with real mail hosts so it is safe to block all such connections. This blocks high amount of spam for us.