In a previous thread

Subject: Re: iPhone/iPad IMAP connection bursts causes user+IP exceeded

I reported the behaviour of MacOSX/iOS IMAP readers whereby it would use up all available connections (up to the mail_max_userip_connections setting) for mailbox searches, then log them all out, then repeat the cycle with another batch of mailbox searches, until all mailboxes were scanned.

However, login/logout log counts don't square up. I would observe (for a particular user+ip) mail_max_userip_connections login entries, followed by *fewer* than mail_max_userip_connections logout entries. (I could not find any disconnections or other forms of termination.)

mail_max_userip_connections), then another strings of logouts fewer

The next peak connection count happened after another mail_max_userip_connections logins (implying the total connection count than mail_max_userip_connections.

For example, if mail_max_userip_connections=100, I would see

0 -> 100 logins -> 87 logouts -> 100 logins -> 87 logouts
-> 100 logins -> 94 logouts -> 100 logins -> ...

It appears that somewhere, somehow, IMAP session exits are not being logged. Is there a reason to explain this discrepancy?

Joseph Tam <jtam.home@gmail.com>