To further test the TCP/IP stack, start a server application on one computer, and a client program on the other computer, and test whether they can communicate properly.
There are several applications commonly provided with TCP/IP implementations that can be used for this purpose. To use the telnet command to test the TCP/IP stack:
Start a Telnet server process (or daemon) on one machine. Check your TCP/IP software documentation for instructions. For a typical command line Telnet program, enter this at the command prompt:
telnetd
Start the Telnet client process on the other machine, and see if you get a connection. Again, check your TCP/IP software documentation for instructions. Typically, enter an instruction similar to:
telnet server_name
where server_name is the name or IP address of the computer running the Telnet server process.
Establishing a Telnet connection between these two machines indicates that the protocol stack is stable and the client and server should be able to communicate using the TCP/IP link. If you cannot establish a Telnet connection, there is a problem. Before proceeding with additional diagnostics, ensure that your TCP/IP protocol stack is working correctly.