Weird problems with pop3d

[Alexandre BOULANGER]

Hi all,


I'm using since 2 years a few Debian mail servers, now running Cyrus
2.1.18, both with imapd and pop3d activated.
I have perdition as proxy for mapping user at domain logins to the format
they're stocked into Cyrus, nothing more.

I've got a major problem since 1 month now; sometimes POP3 users cannot
retrieve their mail, but they could see it in our Webmail or with IMAP.
This happens very randomly at some users.

Looking deeper at it, it seems that the content of some messages make
the pop3d process to hang, and keep the mailbox locked; to unlock it I
have to kill the POP3 process, delete the mail with IMAP and expunge the
mailbox.


I've fsck'ed the whole server and found nothing; my max list of open
files isn't reached, moreover I've recompiled a kernel with an increased
value, disabled APOP and TLS stuff, searched the Cyrus archives for
similar matters but found nothing.

Of course I have no problem with IMAP, but I will still have users using
POP and complaining about mailboxes being blocked, without knowing
exactly why.


Does someone have an idea? or debug methods I can use (except checking
logs in $cyrushome/log/$myuser)


TIA

-- 
Alexandre BOULANGER <a.boulanger at askus.fr>