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Hi, Im not sure if this has been talked about before, I wasnt able to find
anything when I looked through the archives either.
Here's whats going on. We are using LVS for load balancing imap servers,
we have the tunneling option set up so the individual servers reply to
the client.
We are seeing a problem if you have your email client set up to copy
sent messages to a "Sent" folder on the imap server. The client opens
a seperate connection to the imap server for the sent folder. The
problem is if you are typing a message and you have it open for a while
(20 or 30 minutes) the imap connection for the sent folder is timed out.
It tries sending it through the old connection (port) and gets "Port
Unreachable" error from the imap server (not the LVS server) when it tries
copying the message to sent mail. It will re-open the connection after a
bit, but not when it is trying to to the sent mail thing.
It seems that after 30 minutes the imap server sends a "BYE" message
because it has been idle too long, and it does an autologout for the
corresponding folder. This should be followed by a FIN, and then ACK from
the client. In this case the ACK is not making it to the server, but
being rejected with "Port Unreachable" messages, so the server keeps on
trying to close the connection.
This problem doesnt happen if you use an imap server directly and not the
LVS server for the load balancing.
That is just a really fast description, if I wasnt clear enough let me
know and I will explain better. Just wondering if anyone else seen a
problem like this? Or knows how to fix it?
Kris Odland
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Kris Odland -- ITS Server Group
IACC 242K -- NDSU
(701) 231-9646 Kristoffer_Odland@xxxxxxxxxxxxxx
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