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I am trying get a response from the server by using the command echo 'my message' | nc -l -u 2947

But I get nc:Address already in use. for a response. How do find the reason for this message?

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A process is probably already listening on UDP port 2947. You can get the PID of the process by running:

fuser -n udp 2947

Or browse the list of listening UDP ports to find your process:

netstat -plun
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Thank you.Now I changed the port number and used nc command with new port number.Now it just hangs.It works with TCP and gives 'connection established' message. – CodeBot Jun 6 '13 at 4:14

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