server.py

#!/usr/bin/python
import socket
srvsock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
srvsock.bind(('', 6000))

while 1:
	msg, (remoteHost, remotePort) = srvsock.recvfrom(100)
	print 'Server: ', msg
	if msg != 'quit':
		srvsock.sendto(msg, (remoteHost, remotePort))
	else:
		msg = 'Bye-bye'
		srvsock.sendto(msg, (remoteHost, remotePort))
		print 'Server: ', msg
		break

srvsock.close()

client.py

#!/usr/bin/python

import socket
clisock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
clisock.sendto("Hello World, Joe Black", ('', 6000))
print 'Client: ', clisock.recv(100)
clisock.sendto("quit", ('', 6000))
print 'Client: ', clisock.recv(100)
clisock.close()

运行结果：

server:

[zcm@python #77]$./server.py 
Server:  Hello World, Joe Black
Server:  quit
Server:  Bye-bye
[zcm@python #78]$

client:

[zcm@python #47]$./client.py 
Client:  Hello World, Joe Black
Client:  Bye-bye
[zcm@python #48]$