Accessing Web Service Through ISA Server with Proxy enabled

[John Bown]

This query is similar to some others on this discussion group, but none of
them were resolved! Can anybody help:

The issue is related to integrated authentication. First I'll describe a
simple scenario not involving ISA server, which works as expected:

The web service is hosted on a server in the same domain as my workstation
with anonymous access denied, and integrated authentication enabled.

If I access the web service using the following code snippet, everything
fails with an authentication error, AS EXPECTED:

oWebService = New {my web service}
oWebService.Url = {url of deployed web service}

If I set credentials, and access the web service using the following code
snippet, everything succeeds as expected:

oWebService = New {my web service}
oWebService.Url = {url of deployed web service}
oWebService.Credentials = System.Net.CredentialCache.DefaultCredentials

So far so good. And now the problem scenario:

Now place ISA server in the way, configured as an outgoing proxy between my
workstation and the hosted web service. ISA server is configured to require
integrated authentication, and the HTTP redirector configured to use the Web
Proxy service.

If I now access the web service using the first code snippet, everything
fails with a 407 authentication error. Again this is as expected:

oWebService = New {my web service}
oWebService.Url = {url of deployed web service}

However, if I now set credentials, and use the second code snippet:

oWebService = New {my web service}
oWebService.Url = {url of deployed web service}
oWebService.Credentials = System.Net.CredentialCache.DefaultCredentials

This has no effect. I still get a 407 authentication error. Examining the
ISA logs it appears that the access to the web service is still being
attempted with an anonymous connection.

Very grateful for any answers, or suggestions. It is ISA Server 2000 with SP2.