Greylisting .. nice ..

Jim Holland mailscanner at
Sat Nov 4 06:53:19 GMT 2006

On Sat, 4 Nov 2006, Res wrote:

> Date: Sat, 4 Nov 2006 11:48:21 +1000 (EST)
> From: Res <res at>
> Reply-To: MailScanner discussion <mailscanner at>
> To: MailScanner discussion <mailscanner at>
> Subject: Re: Greylisting .. nice ..
> On Fri, 3 Nov 2006, Rob Poe wrote:
> > My thoughts so far are this:  Why didn't I do this sooner.
> Its going to be pointless soon, problem is, as more and more people do
> this, it wont be long before the common garden variety spammers smtp
> engine will also retry on 4xx errors, id give it a year tops (if some of
> them are not already doing it)

My objection to it is not that it doesn't work, but that it makes all
genuine mail servers work twice as hard to deliver mail.  I like having an
outgoing mail queue as clean as possible, and the greylisters mean
multiple retry attempts before the mail can be delivered.  The more people
adopt it the harder it is going to get for the rest of us.  And if the
spammers adapt to it then we are all going to face a massive increase in
the number of connection attempts they make on us to defeat greylisting,
and Internet bandwidth will become even more congested than it is at the

It reminds me of the arguments for keeping a gun in the house - "I just 
want to make sure that I can protect my family against a dangerous world".  
But if everyone did just that the world would become an even more 
dangerous place.

There are definitely no guns in my house.


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

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