title: Using SO_REUSEADDR - What happens to previously open socket?
body: <p>In network programming in unix, I have always set the SO_REUSEADDR option on the socket being used by server to listen to connections on. This basically says that another socket can be opened on the same port on the machine. This is useful when recovering from a crash  and the socket was not properly closed - the app can be restarted and it will simply open another socket on the same port and continue listening.</p>
  
  <p>My question is, what happens to the old socket? Without a doubt, all data/connections will still be received on the old socket. Does it get closed automatically by the OS?</p>