WCF NetTcpBinding, remote client Established TCP Ports do not recycle

Question

In our application we have bunch of WCF services(NetTcpBinding) hosted under Windows Service, we have a remote client/clients which is connecting to this wcf service.
When Network connection drop between client and Server, I am seeing that Established TCP Ports does NOT get recycled, When we get Network connectivity back and remote client app try to connect to the service again, we see new TCP Ports getting created again,
but old TCP Ports still remain open, we have set ReliableSession to true and ReceiveTimeOut to 10 min on our WCF Service.
Could anyone know here why this connection never gets recycled, what we have to do specific to have them cleanedup if remote client either crashes or network connection drops.

Answer 1

You are probably closing the TCP connection simultaneously from both the client and server.  There is a design issue with TCP going back to the 1970's that has never been fixed.  When connections are closed from both ends at the same time sometimes
ports are left open in a half open / half close state.  The correct method for closing TCP is as follows
1)  From application level client send command to stop server
2) Client closes connection
3) Server uses the on closed event to dispose server objects so no memory leak occurs.
jdweng