PYTHON: simple scanner in python

this is a simple scanner in python.

work: call a system ping (with popen() ) and look for ttl count.
if count ~64 -> linux, count ~128 -> windows, count ~255 -> BSD/Router

then it connect to well known ports and look for respond.

limits: only certain ports and only TCP

trace2.py
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#!/usr/bin/python

import sys, os, socket, re


class Scan:
  def __init__(self):
    #print "create socket ..."
    self.scanNew=None
    self.allPorts={"ftp-data":20, "ftp":21,"smtp":25, "http":80, "pop3":110, "imap3":220,  "https":443,
                    "ldap":389 }
    self.linuxPorts={"ssh":22, "dns":53, "snmp":161, "snmp-trap":162}
    self.windowPorts={"netbios-ns":137, "netbios-dgm":138, "netbios-ssn":139,"microsoft-ds":445 }

  def ping(self, ip):
    findttl = re.compile(r"ttl=(\d{1,3}) ")
    pingpipe = os.popen("ping -W 1 -c 1 "+ip,"r")
    for line in pingpipe.readlines():
      if "ttl" in line:
        result = re.findall(findttl,line)
        return int(result[0])
    return -1  

  def connectTCP(self, ip, port, portname):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.settimeout(1)
    try:
      s.connect((ip, port))
      print "connect to %s : %d (%s) was succesfull"%(ip, port, portname)
    except:
      pass
      #print "failing to connect %s : %d (%s)"%(ip, port, portname)
    s.close()

  def scann(self, ip):
    ttl=self.ping(ip)
    if( ttl==-1):
      print "IP %s not reachable"%ip
    elif( ttl==0 ):
      print "huch, ttl is zero"
    elif( ttl>0 and ttl<65 ):
      print " %s possible LINUX and is Alive"%ip
      for port in self.allPorts.keys():
        self.connectTCP(ip, self.allPorts[port], port)
      for port in self.linuxPorts.keys():
        self.connectTCP(ip, self.linuxPorts[port], port)
    elif( ttl>64 and ttl<129 ):
      print " %s possible WINDOWS and is Alive"%ip
      for port in self.allPorts.keys():
        self.connectTCP(ip, self.allPorts[port], port)
      for port in self.windowPorts.keys():
        self.connectTCP(ip, self.windowPorts[port], port)
    else:
      print " %s possible BSD or Router and is Alive"%ip
      for port in self.allPorts.keys():
        self.connectTCP(ip, self.allPorts[port], port)
      for port in self.linuxPorts.keys():
        self.connectTCP(ip, self.linuxPorts[port], port)

if( len(sys.argv) != 4):
  print "%s ip(first triple) begin end"%sys.argv[0]
  print "  example:"
  print "  %s 123.45.67  10 20"%sys.argv[0]
  sys.exit(2)

iptriple=sys.argv[1]
begin=int(sys.argv[2])
end=int(sys.argv[3])

scan=Scan()

for ip4 in range(begin, end):
  ip="%s.%d"%(iptriple,ip4)
  scan.scann(ip)

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