Question

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, # Internet
                      socket.SOCK_DGRAM ) # UDP
sock.bind( (UDP_IP,UDP_PORT) )

while True:
    data, addr = sock.recvfrom( 1024 ) # buffer size is 1024 bytes
    print "received message:", data,"from", addr

The client:

import socket

UDP_IP="127.0.0.1"
UDP_PORT=5005
MESSAGE="Hello, World!"

print "UDP target IP:", UDP_IP
print "UDP target port:", UDP_PORT
print "message:", MESSAGE

sock = socket.socket( socket.AF_INET, # Internet
                      socket.SOCK_DGRAM ) # UDP
sock.sendto( MESSAGE, (UDP_IP, UDP_PORT) )

In the server, I modified the last line:

        print "received message:", data,"from", addr

so it prints the address that the message was sent from.
On my macbook the port seems to be some random number between 40000 or 65000 (i’m just sure it seems random).

Any idea what this could be ?

Answer 1

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