This will work in Python 3
import urllib.request
user_agent = 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.7) Gecko/2009021910 Firefox/3.0.7'
url = "http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers"
headers={'User-Agent':user_agent,}
request=urllib.request.Request(url,None,headers) #The assembled request
response = urllib.request.urlopen(request)
data = response.read() # The data u need