Why are mails sometimes queued not sent ?

[Chushia]

I have a server 9000/800 with HP-UX 11.11. It sends out reports every morning to recipients on our Exchange Server (xyz.com). All went well until recently that some mails were queued but not sent right away. For example this morning, the mail log shows:

Feb 3 08:06:03 hp5430 sendmail[21102]: IAA21102: to=aly.nensi@xyz.com, delay
=00:00:00, mailer=esmtp, stat=queued
...... each recipient has a line like that

An hour later,
Feb 3 09:19:07 hp5430 sendmail[26424]: IAA21102: to=kevin.brown@xyz.com,...,all recipient in one line...ctladdr=sdc
(104/550), delay=01:13:04, xdelay=00:00:00, mailer=esmtp, relay=xyz.com. [17
2.xx.x.xxx], stat=Sent (M2006020309212120925 Message accepted for delivery)

From the log all it tells is it's delayed. Anywhere I can check why?
The server has not been rebooted for half of a year. Could that be the reason ?

Thanks,
Chushia

[Ivan Ferreira]

Use mailq -v to check the status of the outgoing queue. This could be a name resolution issue or the remote host is not available at that time.

Use sendmail -q to force the queue processing.

[Uday_S_Ankolekar]

Is sendmail process running? My first guess would be sendmail is not running or it's ruunning periodically through a cron job.
If you want to push fast then run sendmail with -bd option to run in background

-USA..

[Rick Garland]

Could be a resolution issue as stated but do look at the logs on exchange as well. Is it delaying the receiving of the messages?

Per the HPUX side, the mail will be delivered. Are you receiving any messages saying the mail could not/was not delivered?

[Chushia]

Thanks for the quick reply.

It went by itself. Now the Q is empty.
The sendmail is runing all the time.
As by our Admin, the Exchange Server had no issue. Also there were a bunch of emails going out before and after this email, and they were all OK.

[Chushia]

Hi Rick,

It's not delayed receiving the message.

On the HPUX side, the sender didn't get any messages about the mail being delayed or so ...

[Bejoy C Alias · Accepted solution]

Check for the parameters used to start sendmail in /sbin/init.d/sendmail . normally it is 'sendmail -bd -q30m' where 30m means the interval between queue processing. when a mail arrives in the server the server will try to deliver the mail at the same time , but b'coz of any reason if the mail was not able to deliver at the same time, the next processing will be after 30 minutes ( 30m option given to sendmail startup script ).

Also the mail delivery is depends on the load average of the server . there is one QueueLA option in sendmail which specifies the load average at which the server should only queue the mail and not to deliver . Ur pblm may be because of this . Normally it is 8. SO if the load average of the server is above 8 and a mail comes at that time , then the mail will be just queued and it will not be send until the load average become less than 8.

[Steven E. Protter]

Shalom Chusia

Reasons mails not sent:

DNS lookup fails.
Server you relay through fails to acccept them.
The message is not deliverable due to errors or spam policy at the receiving server.
The user of the email is unknown.

Sendmail is quite tricky and if you deal with those factors above that are in your control the best you can do is minimize the problem.

SEP

[Chushia]

Bejoy answered my Question.

There is a case happening right now and the load average was 9 (>8).

It looks like I really need to re-boot the server now to clenup up some hung proceses.

Thanks all,
Chushia