WCF No connection could be made because the target machine actively refused

Well, I got this error message when I forgot to install necessary components. see link Configuring WCF Service with netTcpBinding

(summary of steps)...

  • Go to "Programs and Features" (usually in control panel)
  • Go to "Turn Windows features on or off"
  • (assuming VS2012) Go to ".NET Framework 4.5 Advanced Services"->"WCF Services"
  • Enable "TCP Activation"

Do you use 192.x.x.x on both client and server? I remember seeing an issue a while back in which for TCP the client and server names needed to match (something related to one of the message properties), so if you define the service with "localhost" and the client with <machine name> there would be a problem.


The physical client and service addresses can differ if the logical address is the same and the server endpoint has been configured with a "listenUri" and the client behaviour is configured to use a <clientVia> address. In our case, this is required in for our proxy/firewall configuration. In effect, the client calls the firewall and the server listens locally for a forwarded request.

For an IIS-hosted service, check the following:

  1. The Application pool is started and looks correct (.NET 4 etc/security)
  2. For NET.TCP, ensure the "Allowed Protocols" in the Web Site/Application (via advanced settings) are configured correctly: e.g. http,net.tcp

For a non-IIS hosted service, you may need to configure a Namespace Reservation (URLACL). http://msdn.microsoft.com/en-us/library/ms733768.aspx

Also ensure the appropriate Windows Services are running, e.g. Net.Tcp listener.