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Trying to set up Exim on Ubuntu 16.04, and I'm getting it to send mail decently, however there are times I push batches of e-mails to the mail server (50+ at a time).

The default configuration seems to be that it won't take more than 10 per connection.

I have chosen the "monolithic configuration file", however I cannot figure out how to:

  • Change parameters, specifically "smtp_accept_queue_per_connection", as I don't know what file to edit, I've tried:
    • /etc/exim4/conf.d/main/00_local_settings
    • /etc/exim4/update-exim4.conf.template
    • /etc/exim4/exim4.conf.local

I also do not know how to verify that the change took place (exim read and understood the config) since I have to wait for our system to send > 10 e-mails, at which time it is losing critical messages.

Any idea where the correct configuration would be, and where I can set that value?

1 Answers1

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You should be able to regenerate and reload the configuration by running the command systemctl reload exim4. The running configuration is the file /var/lib/exim4/config.autogenerated.

I believe the property you want is smtp_accept_max_per_connection. However, this defaults to 1000. I believe this should be set in /etc/exim4/exim4.conf.localmacros, see the man page update-exim4.conf for details.

Try sending the batches over one connection rather than a large number of concurrent requests. You may be hitting connection limits.

Try monitoring the file /var/log/exim4/mainlog when sending a batch of messages. There should be messages telling you which limit has been hit there. You can also use less or more to scan the log for a time when a batch stalled.

Full documentation is included in the Exim4 specification. This also has links to related documentation.

BillThor
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  • Bill, Thank you. In Ubuntu, the limit was defaulted to 10 per connection. I was sending over 50 to it which is what caused the issue. Per your information, the config file that did it for me was "/etc/exim4/exim4.conf.localmacros", I was using the same file without the word "macros" at the end, hence why it failed. Thanks again for the help. – user6262626262 Jan 25 '18 at 15:56
  • Just a note that this approach also works for `smtp_accept_max`, which defaults to 20. – EdwardTeach Dec 10 '21 at 22:07