This is a strange problem.

I have some IIS backed web services. I have one machine (call it machine A)
that acts as the server and listens for these web service calls. There is
another machine (not .NET if it matters) that is a server for some web
service calls (call this machine B). I can make calls just fine into machine
A and from machine A I can make web service calls to machine B. The problem
that I am having is that sometimes the web service call (for which machine A
is the server) needs make web service calls to machine B. When the web
service calls to machine B are made as part of (or inside of) the handler for
web service calls on machine A they get a web exception
(System.Net.WebException ConnectFailure). This does not occur when I make
these calls "directly" only when a web service is calling this other web
service.

To further complicate the issue putting a proxy or port forwarding tool in
the path to the calls to machine B seems to make the problem go away.

Any ideas why my web service cannot make calls to another web service? I am
suspecting there is some kind of corporate firewall issue but I can't prove
it.

Thank you.

Kevin Burton