Question

I wrote a server that is listening for incomming TCP connections and clients connecting to it. When I shut down the server and restart it on the same port, I sometimes get the error message EADDRINUSE when calling bind(…) (error code: 98 on Linux). This happens even though I am setting the option to reuse the socket.

The error does not happen all the time, but it seems that it happens more often when clients are connected to the server and sending data while it shuts down. I guess the problem is that there are still pending connections while the server is shut down (related topic: https://stackoverflow.com/questions/41602/how-to-forcibly-close-a-socket-in-time-wait).

On the server side, I am using boost::asio::ip::tcp::acceptor. I initialize it with the option “reuse_address” (see http://beta.boost.org/doc/libs/1_38_0/doc/html/boost_asio/reference/basic_socket_acceptor.html). Here is the code snippet:

using boost::asio::ip::tcp;
acceptor acceptor::acceptor(io_service);
endpoint ep(ip::tcp::v4(), port);
acceptor.open(ep.protocol());
acceptor.set_option(acceptor::reuse_address(true));
acceptor.bind(ep);
acceptor.listen();

The acceptor is closed with:

acceptor.close();

I also tried using acceptor.cancel() before that, but it had the same effect. When this error occurred, I cannot restart the server on the same port for quite some time. Restarting the network helps, but is not a permanent solution.

What am I missing?

Any help would be greatly appreciated! 🙂

Answer 1

These were originally a comment to the question.

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does your server fork child processes? Also, are you sure the socket is in TIME_WAIT state? You might want to grab the netstat -ap output when this happens