[Dovecot] IMAP timeout

Hi there! Is it possible to set timeout for IMAP connection somehow? The problem is when I'm using mutt to access IMAP mailbox, everything works fine, but after some idle time mutt tells mailbox is closed and next connection crashes it. With courier mutt works just fine, so I think may be dovecot have some timeout which need to be adjusted? I checked manuals and configuration, but no luck...

In both cases (dovecot/courier) I'm using IMAP over SSL

-- Eugene N Dzhurinsky