pf -v- cached imap connections in Thunderbird on windows

[Lisa Muir]

Guys,

Got a problem that I have reproduced on multiple sites, each time with
windows clients, xp, win7 and win8, each time with Thunderbird
accessing an IMAP server, which I have reproduced on my own site with
win 7, but can't reproduce with my debian icedove mail against the
same server.

symptom - everything works fine initially, but after a period, when a
user clicks on a new message, the mail client sits there for a very
long time before loading the message. Restarting the mail client in
safe mode, or just restarting it resolves the issue.

Reducing the number of cached imap connections in the accuont from the
default 5 to 1 imrproves the situation but does not cure it.

Cannot reproduce the problem on sites using the same mailserver which
are not behind a PF gateway.

I believe that PF has killed the cached connection, and when TB tries
to talk through it, it patiently wait for an answer.

I've looked at the
set timeout option value
directive for pf, but cannot determind it is what I want.

Will changing the "interval" or "src.track" likely help my situation
if I am correct in thinking that it is PF that is killing the cached
connection before TB has finished with it?

Lisa.