Subject: (response to message of Mon, 14 Jun 1999 15:40:37 -0400)

From: Steve Barber <[email-masked]>
Date: Mon, 14 Jun 1999 15:40:37 -0400

I've tried going through the archives to find something about this,
with no luck so far.

We have a Solaris server running the U of Washington IMAP server (4.5).
It's in a very standard out-of-the-box configuration.  (/var/mail,
unix mailbox driver, paths relative to homedirs, etc.)

My boss (Windows NT), several other NT users, and at least one Mac user
(all using Netscape Messenger as the IMAP client - 4.5 or newer) are all
having problems like the following:

They will delete a message or a block of messages, and seconds later the
messages will reappear.  This does not happen all the time, but frequently
enough to be highly annoying and time consuming.

They are also seeing "compaction failed" messages when they try to compact
their mailboxes (in Netscape-speak).

I don't believe this is specific to my build or environment because
another admin on the other side of campus (on his own subnet with his
own servers and daemon build) said he was seeing the same thing from an
SGI client running Netscape 4.5.  (I used Netscape IMAP for several
months from an SGI and never saw this as far as I can remember.)

I'm just getting into the heart of the IMAP code and learning the protocol
so that I'll have some idea where to start, but I wanted to see if this
was a well-known problem before I spent too much time on it.  It's not
clear to me if this is a server or client issue yet.

The only clue I have so far is a network snoop of an attempted mailbox
compaction that failed.  I think I can post that if need be.
First glance shows an EXPUNGE failing on a "readonly" mailbox.  I'm
not sure I have enough context in the snoop to know which mailbox
it's referring to.  FWIW, it does not appear to be a permissions problem.

Steve
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From: Mark Crispin <[email-masked]>
Date: Mon, 14 Jun 1999 13:22:53 -0700 (PDT)

On Mon, 14 Jun 1999 15:40:37 -0400, Steve Barber wrote:
> it's referring to.

I think that you've found the smoking gun.

I assume that you've already checked the permissions on the mailbox, and on
both /tmp and /var/tmp (these should be 1777).

There is a known bug in imap-4.5 toolkit which may be related to your problem.
The standard UNIX format of mail only permits one session at a time to access
any standard-format mailbox.  The way things are supposed to work, when a
second session opens the mailbox read-write, it kills the first session.  The
idea is that the first session is probably abandoned.

In imap-4.5, the first session keeps a lock on the mailbox, and the second
session goes read-only.  This is caused by a bug -- it is not a designed
change.

The fix to this is to upgrade to the imap-4.6.BETA.
	ftp://ftp.cac.washington.edu/mail/imap-4.6.BETA.tar.Z

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From: Steve Barber <[email-masked]>
Date: Tue, 15 Jun 1999 00:03:30 -0400

> both /tmp and /var/tmp (these should be 1777).

Hm... the server is a Solaris 2.4 system and /tmp was 0777.  Crucial
to the problem at hand?

> session goes read-only.  This is caused by a bug -- it is not a designed

The implication here is that there are multiple sessions to the single
mailbox.  However, this has been known to happen when we KNOW no other
systems are accessing the mailbox.  So unless Messenger is opening multiple
sessions (as Dimitri(?) suggested in another response), I don't believe
this to be happening.

Question: this is a production server.  Is there any way to get useful
logging information out of the imap daemon without breaking things for
the user population?  I.e. something along the lines of sending it a signal
to increase/decrease logging level?

> 	ftp://ftp.cac.washington.edu/mail/imap-4.6.BETA.tar.Z

I'll get that into place ASAP and see if it helps.

Thanks,
Steve

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From: Mark Crispin <[email-masked]>
Date: Mon, 14 Jun 1999 21:35:27 -0700 (PDT)

> Hm... the server is a Solaris 2.4 system and /tmp was 0777.  Crucial

0777 is OK, but generally 1777 is preferred for security.

> So unless Messenger is opening multiple
> sessions

This can happen in Messenger.

> to increase/decrease logging level?

In general, all the information that you'd want in a log is transmitted to the
IMAP client.  During the SELECT command, the IMAP server said why the mailbox
was opened read-only instead of read-write.

> I'll get that into place ASAP and see if it helps.

OK.  Let me know if this solves your problem.