Socket Options

SO_REUSEADDR - allows binding a socket to a local address that was just recently released, without waiting for the (usual) 30 seconds timeout since it was last released.

Reason: the OS wants to assure any delayed packets sent to this address get dumped.

Symptom: without SO_REUSEADDR, you cannot restart your server until the OS's timeout for re-binding is up. (bind() fails with error "address already in use").

Parameters: int, specifying '1' to allow address re-usage, '0' to disallow that.