when does sendmail try to resend a failed message?

[Steve Post]

If I send out an email from hpux, and the mail server HPUX uses is down, the message will try again 24 hours later.

My questions: How does sendmail know to wait 24 hours before it tries to resend the message? Where is it set? What is this configuration term called anyway?

Steve

[Christopher Caldwell · Accepted solution]

sendmail attempts to retransmit e-mails that failed with a temporary failure (4XX series messages).

Use these timeouts (in sendmail.cf) to tune the timing:

O Timeout.queuereturn=5d
#O Timeout.queuereturn.normal=5d
#O Timeout.queuereturn.urgent=2d
#O Timeout.queuereturn.non-urgent=7d
O Timeout.queuewarn=4h
#O Timeout.queuewarn.normal=4h
#O Timeout.queuewarn.urgent=1h
#O Timeout.queuewarn.non-urgent=12h

sendmail will attempt to resend the mail each time the queue is run (unless you've configured sendmail not to attempt a resend unless the message is older than a configured age--see MinQueueAge).

The config I referenced will return (bounce) a message in five days - it'll send a warning to the sender in 4 hours).

[Steve Post]

Ok. I see the timeout parameters. None of them say 24 hours.
I know I am running sendmail -bd -q30m.

So does this mean it is trying every 30 minutes? If that is the case, something external is probably holding it off for 24 hours.
What do you think?

STeve

[Bill Hassell]

Correct. sendmail will retry every 30 minutes and keep trying for up to 3 days (using standard sendmail.cfg file). You will probably find the 'real' failure in /var/adm/syslog/mail.log

Find the original message ID number (hint: type the command mailq), then search for that number in the mail.log file. You'll see the retries and also the failure messages.

[Steve Post]

Thanks guys.

STeve

[W.C. Epperson]

To clarify Bill's response, the "-q30" sendmail command option causes sendmail to _sweep the queue_ every 30 minutes. Whether a delivery attempt occurs for a given message during a given queue sweep will also depend on things like MaxQueueRunSize, MinQueueAge
, QueueSortOrder
, etc.

It sounds like Steve may be taking the queuewarn message for a retry. Default for Timeout.queuewarn is four hours, but could be set to 24 at his site.