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. The following procedure shows how 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 to see how to do this. For a typical command line Telnet program, type the following instruction 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 to see how to do this. For command line programs, you typically type the following instruction:
telnet server_name
where server_name is the name or IP address of the computer running the Telnet server process.
If a Telnet connection is established between these two machines, the protocol stack is stable and the client and server should be able to communicate using the TCP/IP link between the two computers. If a Telnet connection cannot be established, there is a problem. You should ensure that your TCP/IP protocol stack is working correctly before proceeding.