153 will not deliever from the Outbound

Steve Freegard steve.freegard at fsl.com
Fri Aug 18 16:41:51 IST 2006

Hi Billy,

Billy A. Pumphrey wrote:
> Ok....
> On the particular emails that I was checking to make sure that they went
> through have.  So everything is going to iron out looks like.  (Outbound
> down to 23 now)
> However, questions if someone would be so kind to answer them.
> MailScanner was always working fine, it was the exchange machine that I
> messed up and it started blocking connections to only certain emails.  
> What does sendmail do with these emails?  
> Apparently holds on to them until they are delivered and are referred
> to as deffered?  


> There was a log entry that sent a notification to the sender that it
> failed after 4 hours.  What happens after that?  

By default - a notification is sent every 4 hours, then if the mail is 
still undelivered after 5 days a delivery service notification (DSN) is 
sent back to the user stating that the message could not be delivered 
and the message is deleted from the queue.

> Why does it wait so long before trying to send the deffered emails
> again, assuming that is a sendmail setting?  

Could be a number of factors -- by default on a RedHat system the queue 
is run every 15 minutes.

Some systems might set confHOST_STATUS_DIRECTORY which holds a 'cache' 
of hosts and their status and therefore if a host is marked as 'down' 
the messages will be skipped for that host until the cache expires 
(default 30 minutes).

> Can you tell sendmail to process them "now"?

To run force a queue run in the background:

sendmail -q

To run the queue and watch the output

sendmail -q -v

To run the queue and skip using the HOST_STATUS_DIRECTORY (if defined)

sendmail -qR@


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