#!/usr/bin/env python

# DNS query program - Example 4 - DNSquery.py

import sys, DNS, DNSany, re

def getreverse(query):

    """Given the query, returns an appropriate reverse lookup string

    under IN-ADDR.ARPA if query is an IP address; otherwise, returns None.

    This function is not IPv6-compatible."""

    if re.search('^\d+\.\d+\.\d+\.\d+$', query):

        octets = query.split('.')

        octets.reverse()

        return '.'.join(octets) + '.IN-ADDR.ARPA'

    return None

def formatline(index, typename, descr, data):

    retval = "%-2s %-5s" % (index, typename)

    data = data.replace("\n", "\n         ")

    if descr != None and len(descr):

        retval += " %-12s" % (descr + ":")

    return retval + " " + data

DNS.DiscoverNameServers()

queries = [(sys.argv[1], DNS.Type.ANY)]

donequeries = []

descriptions = {'A': 'IP address',

                'TXT': 'Data',

                'PTR': 'Host name',

                'CNAME': 'Alias for',

                'NS': 'Name server'}

              

while len(queries):

    (query, qtype) = queries.pop(0)

    if query in donequeries:

        # Don't look up the same thing twice

        continue

    donequeries.append(query)

    print "-" * 77

    print "Results for %s (lookup type %s)" % \

          (query, DNS.Type.typestr(qtype))

    print

    rev = getreverse(query)

    if rev:

        print "IP address given; doing reverse lookup using", rev

        query = rev

       

    answers = DNSany.nslookup(query, qtype, verbose = 0)

    if not len(answers):

        print "Not found."

    count = 0

    for answer in answers:

        count += 1

        if answer['typename'] == 'MX':

            print formatline(count, answer['typename'],

                             'Mail server',

                             "%s, priority %d" % (answer['data'][1],

                                                  answer['data'][0]))

            queries.append((answer['data'][1], DNS.Type.A))

        elif answer['typename'] == 'SOA':

            data = "\n" + "\n".join([str(x) for x in answer['data']])

            print formatline(count, 'SOA', 'Start of authority', data)

        elif answer['typename'] in descriptions:

            print formatline(count, answer['typename'],

                             descriptions[answer['typename']], answer['data'])

        else:

            print formatline(count, answer['typename'], None,

                             str(answer['data']))

        if answer['typename'] in ['CNAME', 'PTR']:

            queries.append((answer['data'], DNS.Type.ANY))

        if answer['typename'] == 'NS':

            queries.append((answer['data'], DNS.Type.A))

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