I monitor 6 SME servers. All of them have fail2ban active, and I recently added the geoip/xt geoip contribs to all of them. That cut down quite a bit on the number of fail2ban messages I was getting, though I’m not all that convinced that the whitelist option (!=) works as well as it might.
In the last couple of weeks, three of the servers have started having problems sending mail. After trolling through log files, I found all three suffering lots of
Too many connections: 10 >= 10. Waiting one second
entries in the sqpsmtpd log. All of them are being hit by multiple connections, many of them not even being able to make an SSL connection. As an experiment, I wanted to change the INSTANCES figure in the sqpsmtpd runenv. My attempts to create a template fragment to do that have failed miserably. So far, reading the developer’s manual, I’ve not found where I messed up. I’m hoping someone can give me an example of how it should be done.
To complete the experiment, I edited the live runenv and restarted the service. That allowed mail entered through an email client to be sent, even if sometimes slowly.
While it may only be a temporary improvement, I would like to make the change while I investigate other methods of improving the situation. So I really need a way to make changes to the sqpsmtpd or qpsmtpd INSTANCE figures properly.