Could Be OT: How many people only accept reverse DNS lookup mail?

Jim Holland mailscanner at
Mon Aug 21 21:18:08 IST 2006

On Thu, 17 Aug 2006, Michael Baird wrote:

> I've been testing this milter
> as well, on a lower pref MX (Spam Catcher). It goes further then just
> checking reverse DNS, it also checks whether the domain actually accepts
> mail, and if it accepts mail for the specified sender.

I have just installed it on a test machine and found it does what it says 
- ie blocks mail from invalid envelope senders - very well.  However the 
key drawback that stops me from putting it into production is that you 
can't whitelist sender addresses that might be invalid but do send genuine 
mail, eg from mailing lists, web sites, etc.  It also has a very limited 
system for whitelisting hosts - but you have to put them all in one single 
regular expression, which is not very convenient.  It is a pity that it 
isn't integrated with the access file in the same way as require_rdns is.


Jim Holland
System Administrator
MANGO - Zimbabwe's non-profit e-mail service

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