Page 2 - Python and Regular expressions

#!/usr/bin/python2.2
import os
import re
from urllib2 import urlopen, unquote, Request
import base64

#various things needed
linksysurl = "http://192.168.0.1/Status.htm"
linksysuserpass = "username:password"
updateusername = "username:password"
updatehost = "the name of the host you wish to update"

def ExternalIP():
	status = getlinksys(linksysurl)          #Get status page and parse out externalip address
	ipline = re.sub('<.*?>|&nbsp','',status) #parse out html tags and &nbsp
	ipline = re.sub(';','\n',ipline)         #change semicolons to new lines in order re.findall to work
	ip = re.findall ('IP Address:.*',ipline) #parses out ip[0] = internal IP and ip[1] = external IP
	ipiwant = re.sub ('[^0-9\.]','',ip[1])

	#Check if the oldip = newip and if so return "error code"
	file = open("/tmp/oldip",'r')
	oldip = (file.read())
	if ipiwant == oldip:
		return 1
	#write newip to file for later checking
	file = open("/tmp/oldip",'w')
	file.write(ipiwant)
	file.close
	return ipiwant

def UpdateIPAddress():
	externalip = ExternalIP()
	if externalip == 1:
		return 1
	#Uses unix program ez-ipupdate to update ip
	os.system ("ez-ipupdate --address " + externalip + " --user "+updateusername+
	" --service-type dyndns --host " + updatehost)

def getlinksys(url):
	#get the webpage and return it
	req = Request(url)
	# for some reason must base64 encode the username and password
	userpass64=base64.encodestring(unquote(linksysuserpass)).strip()
	req.add_header('Authorization', 'Basic ' + userpass64)
	return urlopen(req).read()

UpdateIPAddress()