We are trying to build client and server components using WIN32 socket APIs. Code does work when the client code is standalone console application, but when converted to NT Service to run in background asynchronously it fails to connect to the server. We receive error code 121 (which is Semaphore timeout is expired) Case 1: Server code is residing remotely. Client code is local - It fails with above error Case 2: Server and client code are local it works well Case 3: Server and client code on remote machines, it work well. We have issues with Case 1 and unable to figure this out. Please help. Thanks Bala