[Greylist-users] Handling servers that don't wait on their retries

William Blunn bill--greylist at blunn.org
Thu Feb 26 02:49:39 PST 2009

Ian Ballantyne wrote:
> the block expires.  These retries are usually spaced only a few seconds apart, 
> resulting in hundreds of retries during the block period and an unnecessary 
> server and network load.  I have complained to the server admins, pointing out
> RFC 2821 section, however they do not change their configurations 
> instead telling me their servers are fine.


Remember that you created the problem in the first place by 
*artificially* temporarily rejecting their delivery attempt when your 
server would almost certainly have been in a position to accept it.

I am all in favour of greylisting, but if you are going to bend the 
rules, then you should not do anything which gives outsiders cause to 

If your server rejects a legitimate mail, and later analysis reveals 
that your server made the first mistake, then the blame will stick to you.

If I were in your position, I would be looking to design my incoming 
mail system (in the way of dimensioning the hardware, and choice of 
suitable MTA software (i.e. not Sendmail)) to cope with the "load" of 
repeated incoming delivery attempts --- though why tempfailing delivery 
attempts at RCPT time (i.e. before the strain of DATA) should create 
heavy loading is beyond me.


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