Re: Is gray-listing a one-shot anti-spam measure?

[mimo <mimo@restoel.net>]

Russell Coker wrote:

On Friday 03 December 2004 20:07, Adrian 'Dagurashibanipal' von Bidder 
<avbidder@fortytwo.ch> wrote:
  

(And - this to Stephen Frost, I believe - there is a patch to postgrey
which I will include in the next version, and I believe which will also be
included in the next upstream, to whitelist a client IP as soon as one
greylisted email came through.  So the load on legitimate mailservers will
be even smaller.)
    

As has already been suggested it would be good to be able to configure the 
number of messages that come through before the client IP is white-listed.

Also it would be good to be able to configure the amount of time for which a 
white-list entry is valid.  What is a dedicated mail server today may be part 
of a dial-up IP address range next year...

  

In the implementation I wrote (mimo.gn.apc.org/gps) you would have to modify some lines in db.cpp in the update method. But I think the problem of this would be that initial messages would be even more delayed, depending on the sending server, than they are with normal one-shot greylisting. That already creates a problem (complaints etc since users expect email to be immediate). Though this depends on the configuration, the delays  on standard systems would be massive. exim4 on debian comes with this default:
F,2h,15m; G,16h,1h,1.5; F,4d,6h
Which probably means (I'm guessing) something like a 30 minute delay for the initial message with retry = 2.

mimo