But I've never before heard POP3 clients behaving that way, so I'd like to know what exactly are they doing. Are they not sending anything? Are they NOOPing? I don't see any reason for them to be doing either..
In the cases I've looked into, the client seems to be connected and not doing anything. I don't have access to the clients or end users, but ktrace on the pop3 process basically is producing no output or very little output over an extended period.
Could it be an interactive client which maintains an open pop connection, even when no one is actively doing anything with it?
The "unlock after a few seconds" option would be great.
Do you have any documentation or hints on how to identify or debug connecting pop clients without involving the end user?
Could it be some (older?) webmail clients that use pop3 instead of imap?
I wouldn't expect a webmail client to hold a pop3 connection open across multiple web requests. We have standard webmail clients available for customer use, but they use IMAP. With the frequency we're seeing this problem, I'd expect it's more likely to be something newer or more commonly used.
Alan Ferrency pair Networks, Inc. alan@pair.com