from scapy.all import *
from time import ctime,sleep
import threading
TIMEOUT = 4
conf.verb=0

def pro(cc,handle):
 dst = "192.168.1." + str(cc)
 packet = IP(dst=dst, ttl=20)/ICMP()
 reply = sr1(packet, timeout=TIMEOUT)
 if not (reply is None):
  handle.write(reply.src+" is online"+"\n")
  #print reply.src, "is online"

def main():
 threads=[]
 f=open('ip.log','a')
 for i in range(2,254):
  t=threading.Thread(target=pro,args=(i,f))
  threads.append(t)
 print "main Thread begins at ",ctime()
 for t in threads :
  t.start()
 for t in threads :
  t.join()
 print "main Thread ends at ",ctime()

if __name__=="__main__" :
    main();