[Dovecot] imap connection problems

[Ivan Pesin]

Hi,

Have encountered some strange behavior of dovecot: after few days of 
work (5-7 days, ~50 users, imap over ssl or tls) dovecot stops respond 
with "* OK Dovecot ready.". I.e. connection gets accepted, but no 
response from dovecot:

[ivan at dyn-226 bin]$ telnet imap 143
Trying 192.168.100.9...
Connected to imap.n-ix.com.ua (192.168.100.9).
Escape character is '^]'.

while obvious should be

[ivan at dyn-226 bin]$ telnet imap 143
Trying 192.168.100.9...
Connected to imap.n-ix.com.ua (192.168.100.9).
Escape character is '^]'.
* OK Dovecot ready.

After dovecot restart everything works OK. This behavior we started to 
observe since rc24, before that on rc9 we didn't see that problem. 
Currently running on rc26.

Any ideas?

Thanks,
 Iv