Tom Horsley writes:
What I'd really like to have is something on my desktop that acts
like
an IMAP server, but really forwards requests to the main server, however
it does allow me to do procmail/spamassassin/bogofilter processing of the mail
on the corporate IMAP server so I can delete obvious spam, etc. before
anything talking to my local IMAP server even sees it.
Given the complexity of IMAP, I would be rather surprised if such a beast
ever exists. Most of the other replies to your post have ignored this part
of your requirements.
You're better of with the approach of running fetchmail to download messages
to your local IMAP mailbox (and they'll probably have to be deleted from
your corporate IMAP server, unless fetchmail can keep track of which ones it
already downloaded -- and I don't know if it can) and filtering it on your
local IMAP mailbox.