Exchange Server - RPC over HTTP retries 'fast network' each time user opens something

I have a user that is setup for RPC over HTTP, which generally works
fine, but when we have him set to connect over HTTP for slow, but NOT
for fast networks, it works fine in the office on the LAN, but seems
to retry and retry when he is connected remotely. I changed it to
connect over http over fast or slow networks (so it does not bother to
check the network speed) and it works flawlessly, but prompts him for
ID and password even when he is on the LAN. Obviously this is
functional, but he'd rather not have to put in his ID and password at
the office after he logs on to the domain.

Anybody have any suggestions on what to check to get it to recognize
the slow network and then not recheck and recheck the speed (or retry
and retry, or whatever it is doing when he is working remotely)??

Thanks for any input...

Mick

Is your RPC over HTTP actually working for other users?

Yes, everyone else appears to be working flawlessly.

xt -

Well when you connect over RPC over HTTP, it makes multiple
connections back to Exchange. Try running wireshark to see which
connections are prompting him for the credentials.