On Wed, 08 Mar 2006 17:56:06 -0600, Sam
wrote:

Gerard Bok writes:

Situation: 10 mailboxes on a Courier IMAP server.
Multiple users on multiple locations, all sharing all mailboxes.

Synchronize accounts produces loads of 0x800CCC0F errors.
More specific: at quiet times, I am able to sync each mailbox
individually without any error.
Once I try to sync all accounts at once, loads of errors are
reported, on random mailboxes and even when I just finished an
individual sync.

By mailboxes I presume you are referring to IMAP folders. I doubt that you
are logging in to ten different IMAP accounts.

Well, good question. But I guess we are :-)
There are 10 different email addresses on the server, each with
it's own mailbox and set of log in codes (and it's own aliases).

The default Courier-IMAP server configuration permits a maximum of five
simultaneous connections from the same IP address.

Before we could get this schema going the server's administrator
had to adjust something from 5 upwards. Now it is set to 100
instead. (Due to NAT up to 3 different PCs could be calling the
server from the same IP, so that would make 30 connections.)

It appears that your mail client opens a separate connection for each IMAP
folder. The server refuses to accept any more connections, after the first
five, and then your mail client vomits all over itself.

There definately is going something wrong. Peeking at the
communications shows [TCP Window Full] [TCP Out-of-order]
messages. I never see an indication of a connection being denied
though.

Either increase the maximum number of allowed simultaneous connections, in
the server's configuration file, or switch to a different mail client that
implements IMAP properly.

The first has been done already, I think. And the second is, I am
afraid, not (yet) an option.
Thanks!

--
Kind regards,
Gerard Bok