Huge Mail Queue

[andrei155]

I constantly have a Mail Queue of at least 300 e-mails. I'm not sure if this is normal - however I'm really starting to get concerned. What can I do to prevent e-mails from queuing up? I have a few e-mails that have been stuck there for up to 52 hours.

[cPanelDon]

I constantly have a Mail Queue of at least 300 e-mails. I'm not sure if this is normal - however I'm really starting to get concerned. What can I do to prevent e-mails from queuing up? I have a few e-mails that have been stuck there for up to 52 hours.

There are different ways to handle mail queues; for example:
1.) Determining the reason why e-mails are queued and correcting any problems discovered.
2.) Adjusting the Exim configuration so queued messages have delivery reattempted more frequently.
3.) Adjusting the Exim configuration to have older messages expire from the queue sooner.

I believe option #1 may be the most effective in maintaining the mail queue. Please note that in some instances it may be normal for a system to have a larger mail queue as this depends heavily on the unique server usage and the volume of e-mail traffic that is involved.

The exim logs are a great resource to determine why a specific message is unable to be sent; the Exim mainlog can be found at the following file system path:

/var/log/exim_mainlog

If attempting to force delivery of a specific message in the queue, you may monitor the aforementioned log using the following command via root SSH access:

# tail -fvn0 /var/log/exim_mainlog

If needing to enable more verbose logging I recommend adjusting the "log_selector" directive in the Exim configuration via the Advanced Exim Configuration Editor in WHM; here is an example entry that could be used:

# log_selector = +all -ident_timeout -pid

Here is the full menu path for WHM where the above directive may be added (in the first text entry box in the Advanced Editor):
WHM: Main >> Service Configuration >> Exim Configuration Editor >> Advanced Editor

For more detailed information about the aforementioned "log_selector" directive and what options it has please refer to the official Exim documentation that includes full usage information: Specification of the Exim Mail Transfer Agent: 49. Log files - 49.15. Reducing or increasing what is logged