How to reuse port in socket server application?

Question

I am trying to write a basic server socket program. I use the following code to bind the server socket.

/* Bind the server socket */
if (bind(serversock, (struct sockaddr *) &server, sizeof(server)) < 0)
{
    perror("Failed to bind the server socket");
    exit(1);
}

When I run the program for the first time, it works fine but when I run it the second time, I get this error:

I think when I run the program second time, it gives this error because the port was already linked to program which I run the first time. Can someone tell me how to close the port currently in use? Or suggest me something else which can solve this error.

@KamiKaze I already have `close()` in my program but when I terminate program using ctrl^c, `close()` is not helpful. — Razin, Nov 30 '16 at 14:48

score 3 · Accepted Answer · answered Nov 30 '16 at 14:51

3

Kill the process that binds the port:

 fuser -TERM 80/tcp #kills processes on tcp port 80 using signal SIGTERM

and start again.

TCP sockets normally aren't reusable for a while (a few minutes), unless they had the SO_REUSEADDR option set (with setsockopt) before they were bound.

(This option somewhat decreases robustness, but should be fairly safe to use in a testing environment.)

answered Nov 30 '16 at 14:51

Petr Skocik

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I tried to kill the process that binds the port but it doesn't work. I still have to wait for few minutes to reuse the port. – Razin Nov 30 '16 at 15:04

How to reuse port in socket server application?

1 Answers1