BUG: CIS (DCOM Over HTTP) Broken in SP4 When Tunneling Through Microsoft Proxy Server 2.0

When you use Microsoft COM Internet Services (CIS), also known as DCOM over HTTP, on a Windows NT-based computer to tunnel through Microsoft Proxy Server 2.0, you may receive an error message that the Remote Procedure Call (RPC) server is unavailable.

During an HTTP CONNECT sequence, RPC sends a "CONNECT server:80 HTTP/1.1" string, where server is the name (or TCP/IP address) of the proxy server. This is rejected by Proxy Server 2.0 as a "bad request" because this is not a valid request for HTTP version 1.1. The correct RPC request should be: "CONNECT server:80 HTTP/1.0", where server is the name (or TCP/IP address) of the proxy server.

To resolve this problem, obtain the latest service pack for Windows NT 4.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows NT 4.0 Service Pack 5.