#!/usr/bin/env python
import sys
from scapy.all import *

def findSYN(p):
        flags = p.sprintf("%TCP.flags%")
        if flags == "S":        # Only respond to SYN Packets
                ip = p[IP]      # Received IP Packet
                tcp = p[TCP]    # Received TCP Segment
                i = IP()        # Outgoing IP Packet
                i.dst = ip.src
                i.src = ip.dst
                t = TCP()       # Outgoing TCP Segment
                t.flags = "SA"
                t.dport = tcp.sport
                t.sport = tcp.dport
                t.seq = tcp.ack
                new_ack = tcp.seq + 1
                print "SYN/ACK sent to ",i.dst,":",t.dport
                send(i/t)

sniff(prn=findSYN)