timeouts when connecting to imap server

[Jorey Bump]

Timo Veith wrote:

> I am still having the problem, isn't there anyone who has a hint for me? I 
> changed the io scheduler from cfq to deadline, raised file descriptor 
> limit to 300000 and still have no betterment. :(

Just a thought, but can you try switching to a 2.4.x kernel? The 2.6
series seems to suffer from gremlins like this once in a while.

> I installed the nagios check on the mail server itself to exclude network 
> problems and checked the imap service on both interfaces (localhost and 
> on the external ip). I also did this in parallel and noticed that when a 
> timeout happens on one interface it is not constraining a timeout on the 
> other interface, too.
> 
> How can I tell why it sometimes takes so long until a imap process 
> responds?

I had a similar problem that seemed to disappear when I disabled IDLE on
the client, but does nagios use IDLE? When you look at the users that
are affected, does any particular client or setting stand out?