after execut this command netstat -na
have a display which are showing some listening ports and local address and state
i want know which port i can use for socket c# programming ?

You can use any port you want. But some of them are currently 'reserved' for use by various applications (25 for mail, 110 for PoP, 80 for HTML, etc.)

For general programming use, it is recommended that you use a port from 1024 through 49151. The Internet Assigned Number Authority (IANA) maintains a list of port number that are used by various applications (WARNING: Large list)

i am using 7071 port how to check its valid and conected or able to receive data ?

i am using 7071 port how to check its valid and conected or able to receive data ?

It is valid until no other service uses it. Write a simple client program to check whether its workin