scapy

#!/usr/bin/env python

from scapy.all import *

from random import randint

if __name__ == '__main__':

    ports = [21,22,23,25,80,443,8080]
    
    results = []

    for port in ports:
        (ans, unans) = sr(IP(dst="172.16.42.12", src="172.16.42.45")/TCP(dport=port, sport=randint(1024,65530)))
        if ans[0][1][TCP].flags == 18:
            results += [port]
        
    print results