We have an internal application [written in C#] that has a client piece [using WinForms], a Web Service, and a remoting function to call our application/middle-tier server. We're using the basic remoting functions [remoting client interface, remoting server, etc.] that are found on sites that publish basic code for remoting.

The Web Service is basically a 'communicator' with the middle-tier. The 'face-function' for the middle-tier is an application manager DLL, which is remoted from the web service [we want the web service and the middle-tier to be able to reside on different boxes].

About a week ago, we did a major update of all the DLLs in the middle-tier, but we didn't change the remoting or anything else. Ever since, when we try to connect from the client piece, we get a message back saying 'An existing connection was forcibly closed by the remote host'.

We've rebuilt all the DLLs for the web server and middle-tier, and continue to get this message. When we run our 'older' version [on the same boxes], everything works OK. But when we run the 'newer' version [seemingly the same architecture], we continue to get this message. It appears that something we installed [or didn't install] on either the Web Server or Middle Tier has broken the remoting...but we don't know where.

I realize this isn't much detail, but was just curious if anyone had run into anything like this, and/or could offer any clues.

Thanks,
Kevin