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Socket Options

The POSIX socket interface also supports all sorts of socket options that control specific behaviors of network sockets. These are accessed through the Python socket methods getsockopt() and setsockopt(), using the options you will find documented for your operating system. You can find this options described in the Python documentation.

When setting socket options,the set call is similar to:

value = s.getsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST)
s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, value)

Here are some of the more common options:

• SO_BROADCAST: Allows broadcast UDP packets to be sent and received; see the next section for details.

• SO_DONTROUTE: Only be willing to send packets that are addressed to hosts on subnets to which this computer is connected directly.

• SO_TYPE: When passed to getsockopt(), this returns to you regardless of whether a socket is of type SOCK_DGRAMand can be used for UDP, or it is of type SOCK_STREAM and instead supports the semantics of TCP.

NOTE:

If UDP has a superpower, it is its ability to support broadcast: instead of sending a packet to some specific other host, you can point it at an entire subnet to which your machine is attached and have the physical network card broadcast the packet so that all attached hosts see it without its having to be copied separately to each one of them.Here and here you can find two example of broadcasting.