[Greylist-users] Re: Whitelist entries and 4xx failure codes - Note to implementors

Robert L Mathews lists at tigertech.com
Wed Sep 22 14:03:35 PDT 2004

At 9/22/04 12:00 PM, Evan Harris <eharris at puremagic.com> wrote:

>After getting several whitelist submissions that I can confirm don't
>actually need a whitelist entry (based on my sites logs), I think I have
>narrowed down an issue/detail that may need attention from developers of
>alternate implementations.
>When doing the initial testing of my implementation, I tested the use of
>several different SMTP codes, and 451 was found to be the least problematic
>in that it caused the fewest number of problems with various sites.

I use 450 in my implementation, and I've seen several sites reported as 
requiring whitelisting that actually retry just fine, according to my 

Perhaps the people reporting these are making small mistakes (for 
example, they missed the redelivery attempt when a mail log was rotated), 
or perhaps the problem they observed was transient and not directly 
caused by greylisting (such as the sending mail server crashed and 
corrupted the outgoing mail queue between delivery attempts, or something 
like that).

Not saying all "whitelist needed" reports are bogus, of course, but 
unfortunately a fair number of them seem to be, regardless of whether 450 
or 451 is returned.

Robert L Mathews, Tiger Technologies      http://www.tigertech.net/

 "Ignorance more frequently begets confidence than does knowledge."
                                                           -- Darwin

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