My mail server (running on a Intel Xserve on Mac OS X 10.4.11) has started to behave strangely. Basically, I get tons of unknown connections to my IMAP server, that looks like this:
So, tons of connections from IP-addresses only, no user names. This fills up my available slots and the server becomes unresponsive to new connections. Instead of lifting the limits, I would very much rather find out what the problem is and if there is anything I can do to help this.
When this happens, the /var/log/mailaccess.log file starts to fill with items such as: