On Thu, May 17, 2018 at 10:49:09AM +0200, Igor Zobin wrote:

Hello everyone!

I am struggling to understand what exactly the command lsof -i tcp:389 is showing.

What exactly is counted as an established connection here?

That's a state of the TCP connection:

https://community.apigee.com/articles/7970/tcp-states-explained.html

Can I limit that amount somehow through slapd configuration?

I _think_ that the conn_max_pending and conn_max_pending_auth help control this.

Also, you can use the idletimeout directive to control the disoconnections of unused/stale connections.

The docs also discuss the keepalive directive, but I've never used that.

Can I monitor which of those connections shown by lsof are still in use and which just hang around doing nothing?

IIRC, From lsof, you can learn PIDs and file descriptors. You can access the FD through procfs.

Igor.