checks if a website is using cloudflare

siteatcf.py

#!/usr/bin/env python3

import ipaddress
import requests
import socket

from sys import argv, exit

def getIPs() -> ipaddress.ip_network:
    r4 = requests.get("https://www.cloudflare.com/ips-v4")
    r6 = requests.get("https://www.cloudflare.com/ips-v6")

    ips = [ ipaddress.ip_network(ip) for ip in r4.content.decode().split("\n") ]
    ips = ips + [ ipaddress.ip_network(ip) for ip in r6.content.decode().split("\n") ]

    return ips
        

def resolveHost(host):
    addr4 = socket.getaddrinfo(host, None, socket.AF_INET)
    addr6 = socket.getaddrinfo(host, None, socket.AF_INET6)

    ip4 = [ipaddress.ip_address(str(x[4][0])) for x in addr4]
    ip6 = [ipaddress.ip_address(str(x[4][0])) for x in addr6]

    ips = set([*ip4, *ip6])

    return ips

def main():
    cfips = getIPs()
    ips = resolveHost(argv[1])

    flagTrue = False

    for ip in ips:
        if any(ip in cfip for cfip in cfips):
            print(f"{ip} is in a Cloudflare subnet")
            flagTrue = True
        else:
            print(f"{ip} not in Cloudflare subnet")
    
    if flagTrue:
        exit(0)
    else:
        exit(1)
    
if __name__ == "__main__":
    main()