#!/usr/bin/python3
"""Produce a shell script to sample some DNS servers to see how many allow recursion.

It turns out that about 7% of all possible IPv4 addresses are running
recursive DNS servers willing to answer queries from my house.

"""
import sys, random

if __name__ == '__main__':
    name = 'www.google.com.' if len(sys.argv) < 3 else sys.argv[2]
    for _ in range(1000 if len(sys.argv) < 2 else int(sys.argv[1])):
        print("dig +time=1 +tries=1 @{} {}".format(
            ('.'.join(str(random.randrange(256))
                             for _ in range(4))),
            name))