We are having a very odd transient problem with our IMAP service over SSL. Occasionally in the last couple of months, the SSL IMAP port (993) appears to get clogged - users currently connected via IMAP are still connected, but new users cannot connect on that port. New connections are accepted on the non-SSL port (143). Our SSL enabled websites continue to function. Looking at the TCP state using netstat shows that some connections seem to be stuck waiting for the server to release the connection. The problem is resolved by restarting the IMAP task.
We initially traced this to a user who needed a password reset - in the logs, we could see her trying to connect (3 times per second, once a minute) and that’s around the time we would have the problem. The user was using the Mac Mail application over a Verizon FiOS line. I’m honestly not entirely sure if this user was really the culprit.
We’ve been in touch with Lotus support and not had any luck so far - they suggested that we try a different port or don’t use SSL, neither of which is acceptable in our environment. Has anyone else seen this problem?
Thanks,
Ben Wall