DCOM relay via WebServices

[Dave Edson]

Hello,

I have a legacy DCOM "server" running on Machine A.

I have a C# .NET windows application running on Machine B.

The app running on machine B can access the DCOM server just fine and call
its methods.

If I build a C# Web Service on Machine B, and have that web service try to
access the DCOM server, it barfs. I am literally using the Hello World Web
Services application generated by the new project wizard, I add nothing but
the COM reference to my DCOM object, and then I create a new object and
invoke the method. As mentioned above, the exact same lines of code work in
a regular Windows applicaion.

The barf happens when I invoke the method. I get an 500: Server Error
message in the IE window when I click the Invoke button from the
VS.NET-generated page.

I suspect there is a security setting I need to change.

Can anyone help?

Thanks!
Dave Edson

 

[Dave Edson]

More information:

After turning off the friendly error messages, I find this is the error:

System.InvalidCastException: QueryInterface for interface xx.yy failed.

Of course, I still don't know why.