[Greylist-users] machine gun

Dave Anderson dave at daveanderson.com
Sun Jan 22 17:55:06 PST 2006

** Reply to message from Barb Dijker <barb at netrack.net> on Sun, 22 Jan
2006 16:10:04 -0700

>> No, the block would not be inappropriate (though messages to
>> 'postmaster' should be allowed to get through, somehow).  By retrying
>> so quickly you're violating section of RFC 1123 (STD 3), which
>> states that the retry interval SHOULD be at least 30 minutes (and that
>> you should continue retrying for at least 4-5 days).  If the short
>> retry interval causes trouble, it's your own fault.
>"SHOULD" in the std is a recommendation, not a requirement.

True, but it's a rather strong recommendation -- especially the part
where (in context) it effectively says DON'T RETRY TOO QUICKLY.

>                                                             Most  
>legitimate mail servers frequently retry sooner.  Our delay is set to  
>4 minutes because the average retry time is around 10 minutes!  Many  
>legitimate servers retry in 5.  There is no point in repeatedly  
>giving those connections a tempfail.
>Keep in mind that the recommendations in std3 were written log ago  
>when bandwidth and server performance were several orders of  
>magnitude less than they are today.

I agree that 30 minutes seems rather long in today's environment (I
prefer 5-10 minutes), but 1 minute is awfully short.


Dave Anderson
<dave at daveanderson.com>

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