I'm trying to build a small tcp scanner for a netmask.

The code is as follow:

import socket,sys,re,struct
from socket import *


host = sys.argv[1]

def RunScanner(host):
    s = socket(AF_INET, SOCK_STREAM)
    s.connect((host,80))
    s.settimeout(0.1)  
    String = "GET / HTTP/1.0"
    s.send(String)
    data = s.recv(1024)
    if data:
       print "host: %s have port 80 open"%(host)

Slash = re.search("/", str(host))

if Slash :
   netR,_,Wholemask = host.partition('/')
   Wholemask = int(Wholemask)
   netR = struct.unpack("!L",inet_aton(netR))[0]
   for host in (inet_ntoa(struct.pack("!L", netR+n)) for n in range(0, 1<<32-Wholemask)):
      try:
         print "Doing host",host
         RunScanner(host)
      except:
         pass
else:
   RunScanner(host)

To launch : python script.py 10.50.23.0/24

The problem I'm having is that even with a ridiculous low settimeout value set, it takes ages to cover the 255 ip addresses since most of them are not assigned to a machine.

How can i make a way faster scanner that wont get stuck if the port is close.MultiThreading ?

Thanks !