What Is The Second Part Of The Address Returned By Recvfrom?

I'm using those 2 pieces of code from http://wiki.python.org/moin/UdpCommunication The server: import socket UDP_IP='127.0.0.1' UDP_PORT=5005 sock = socket.socket( socket.AF_INET

Solution 1:

It's an ephemeral port used by the client to send data to the server.

Solution 2:

It definitely is the port. You can verify it on the sender side with print sock.getsockname().

You can as well set it deliberately with e. g. sock.bind(('', 54312)) before the sock.sendto() line.

This could be useful in context where software checks the port range of the sender: Ports 0..1023 are privileged ports - under many OSes only root is allowed to bind to these ports.

However, in the very most cases there is no point in changing it, so it mostly is better to leave it set the way it is.

This port has the meaning to be the 4th element of the tuple identifying a connection or counterpart of a connection. The tuple is (source_ip, source_port, destination_ip, destination_port).