[Discuss] Lost email?

[dsr at tao.merseine.nu (Dan Ritter)]

On Thu, Jun 16, 2011 at 09:26:29AM -0400, Derek Atkins wrote:
> What is the usual retry cycle, and how long until they give up?  I was down for about 6 hours.  I guess I'll see tonight if stuff gets retried at 24h.


Each MTA is different, and can also be customized.

Exim defaults to every 15 minutes for 2 hours, then backs off to
1 hour, 1.5 hours, and so on (1.5x increasing interval) until 16
hours. Then it tries once per 8 hours for four days since the
initial failure.

Postfix won't try more often than once per 1000 seconds, nor less
frequently than once per 4000 seconds, and maxes out at 5 days.

qmail has a quadratic backoff for individual messages. If a
particular host fails twice more than two minutes apart, all
mail destined for it is held for an hour, then retried.

sendmail has too many defaults, depending on distribution.

-dsr-


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