[Mailman-Users] Bounce processing for low/sporadic traffic

Mark Sapiro mark at msapiro.net
Thu Apr 12 08:26:19 CEST 2012

On 4/11/12 6:07 PM, Adam Clark wrote:
>> From what I can gather from the docs, the bounce score:
> * is incremented (by .5 or 1) each day there is a bounce

Actually, only by 1. Contrary to the docs, retryable failures (4xx
status, SMTP errors) are simply queued and retried. Only permanent
failures (5xx status) are scored and these are all scored as 1, even so
called soft failures such as a full mailbox.

> * is reset
> only if no bounces occur within bounce_info_stale_after days


> In particular, the score is *not* altered when a message is delivered
> successfully.

Correct again.

> I have some announce lists with very sporadic traffic.  So it seems I
> need a high bounce_info_stale_after value to ensure that things don't
> reset, but if I have bursts of activity I can easily wind up booting
> addresses that have a few transient failures but still work most of
> the time.
> I guess -- assuming this is how things work -- my question comes down
> to, why doesn't the bounce score get reset or decremented by a
> successful delivery?

Because no one ever implemented it. It would be kludgy at best to do
because no event occurs for a successful delivery so we would have to
remember every message that was sent to a user and every bounce received
would have to be matched to a sent message, and then when a bounce was
received, we'd have to check that there were no messages sent before
that that didn't bounce, and even that isn't good enough because
sometimes bounces can be delayed for several days or more and there's no
guarantee that they are reported in the order that messages were sent.

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    Better use your sense - B. Dylan

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