Python dns.resolver() Examples

def get_domain_dns(domain):
        """Get the DNS record, if any, for the given domain."""
        dns_records = list()

        try:
            # get the dns resolutions for this domain
            dns_results = dns.resolver.query(domain)
            dns_records = [ip.address for ip in dns_results]
        except dns.resolver.NXDOMAIN as e:
            # the domain does not exist so dns resolutions remain empty
            pass
        except dns.resolver.NoAnswer as e:
            # the resolver is not answering so dns resolutions remain empty
            pass

        return dns_records 

def DNSLookup_dnspython(name,qtype,tcpfallback=True,timeout=30):
  retVal = []
  try:
    # FIXME: how to disable TCP fallback in dnspython if not tcpfallback?
    answers = dns.resolver.query(name, qtype)
    for rdata in answers:
      if qtype == 'A' or qtype == 'AAAA':
        retVal.append(((name, qtype), rdata.address))
      elif qtype == 'MX':
        retVal.append(((name, qtype), (rdata.preference, rdata.exchange)))
      elif qtype == 'PTR':
        retVal.append(((name, qtype), rdata.target.to_text(True)))
      elif qtype == 'TXT' or qtype == 'SPF':
        retVal.append(((name, qtype), rdata.strings))
  except dns.resolver.NoAnswer:
    pass
  except dns.resolver.NXDOMAIN:
    pass
  return retVal 

def setnslist_public(self):
    """Fetch NS list from resolver"""
    tcp = False
    nslist = []
    try:
      ans = self.res.query(self.domain+'.', 'NS', tcp=tcp)
    except dns.resolver.NXDOMAIN:
      return None, _("Error: Domain not found")
    except dns.exception.Timeout:
      return None, _("Error: Timeout")
    except dns.resolver.NoAnswer:
      return None, _("Error: No answer")
    except dns.resolver.NoNameservers:
      return None, _("Error: No name servers")
    for i in ans.rrset.items:
      fqdn = i.to_text().upper()
      nslist.append(fqdn)
    self.setnslist_direct(nslist)
    return True, self.nslist 

def lookup_hostname(name,dnsconf=DNS_CONF):
    try:
        resolv = dns.resolver.Resolver(configure=False)
        log.debug("initialize resolver")
        resolv.nameservers.append(dnsconf["nameserver"])
        resolv.domain = dns.name.from_text(dnsconf["domain"])
        resolv.search.append(dns.name.from_text(dnsconf["domain"]))
        log.debug("resolver {} {}".format(dnsconf["nameserver"],dnsconf["domain"]))
        try:
            answer = resolv.query(name)
            addr = answer.rrset[0]
            log.info("lookup host {} at {}".format(name, addr))
        except dns.exception.DNSException as e:#handle nxdomain - not an error
            log.info("instance not found: {}".format(repr(e)))
            addr = None
    except dns.exception.DNSException as e:
        log.error(repr(e))
        addr = None
    return addr 

def test_recursive_query_basic_failure(self):
        resolver = dns.resolver.Resolver()
        domain = dns.name.from_text('example.com.')
        record_type = 'NS'

        with unittest.mock.patch.object(fierce, 'query', return_value=None) as mock_method:
            result = fierce.recursive_query(resolver, domain, record_type=record_type)

        expected = [
            unittest.mock.call(resolver, 'example.com.', record_type),
            unittest.mock.call(resolver, 'com.', record_type),
            unittest.mock.call(resolver, '', record_type),
        ]

        mock_method.assert_has_calls(expected)
        self.assertIsNone(result) 

def test_recursive_query_long_domain_failure(self):
        resolver = dns.resolver.Resolver()
        domain = dns.name.from_text('sd1.sd2.example.com.')
        record_type = 'NS'

        with unittest.mock.patch.object(fierce, 'query', return_value=None) as mock_method:
            result = fierce.recursive_query(resolver, domain, record_type=record_type)

        expected = [
            unittest.mock.call(resolver, 'sd1.sd2.example.com.', record_type),
            unittest.mock.call(resolver, 'sd2.example.com.', record_type),
            unittest.mock.call(resolver, 'example.com.', record_type),
            unittest.mock.call(resolver, 'com.', record_type),
            unittest.mock.call(resolver, '', record_type),
        ]

        mock_method.assert_has_calls(expected)
        self.assertIsNone(result) 

def test_recursive_query_basic_success(self):
        resolver = dns.resolver.Resolver()
        domain = dns.name.from_text('example.com.')
        record_type = 'NS'
        good_response = unittest.mock.MagicMock()
        side_effect = [
            None,
            good_response,
            None,
        ]

        with unittest.mock.patch.object(fierce, 'query', side_effect=side_effect) as mock_method:
            result = fierce.recursive_query(resolver, domain, record_type=record_type)

        expected = [
            unittest.mock.call(resolver, 'example.com.', record_type),
            unittest.mock.call(resolver, 'com.', record_type),
        ]

        mock_method.assert_has_calls(expected)
        self.assertEqual(result, good_response) 

def lookupComputerDnsNames(self):
        dnsresolver = dns.resolver.Resolver()
        dnsresolver.lifetime = 2
        ipdef = attrDef.AttrDef('ipv4')
        if self.config.dnsserver != '':
            dnsresolver.nameservers = [self.config.dnsserver]
        for computer in self.computers:
            try:
                answers = dnsresolver.query(computer.dNSHostName.values[0], 'A')
                ip = str(answers.response.answer[0][0])
            except dns.resolver.NXDOMAIN:
                ip = 'error.NXDOMAIN'
            except dns.resolver.Timeout:
                ip = 'error.TIMEOUT'
            except (LDAPAttributeError, LDAPCursorError):
                ip = 'error.NOHOSTNAME'
            #Construct a custom attribute as workaround
            ipatt = attribute.Attribute(ipdef, computer, None)
            ipatt.__dict__['_response'] = ip
            ipatt.__dict__['raw_values'] = [ip]
            ipatt.__dict__['values'] = [ip]
            #Add the attribute to the entry's dictionary
            computer._state.attributes['IPv4'] = ipatt

    #Create a dictionary of all operating systems with the computer accounts that are associated 

def run(self, terms, variables=None, **kwargs):

        if HAVE_DNS == False:
            raise AnsibleError("Can't LOOKUP(dnstxt): module dns.resolver is not installed")

        ret = []
        for term in terms:
            domain = term.split()[0]
            string = []
            try:
                answers = dns.resolver.query(domain, 'TXT')
                for rdata in answers:
                    s = rdata.to_text()
                    string.append(s[1:-1])  # Strip outside quotes on TXT rdata

            except dns.resolver.NXDOMAIN:
                string = 'NXDOMAIN'
            except dns.resolver.Timeout:
                string = ''
            except DNSException as e:
                raise AnsibleError("dns.resolver unhandled exception", e)

            ret.append(''.join(string))

        return ret 

def validate_no_virus(afile):
    """ Checks a file field against a remote antivirus service
    """
    if not settings.CAMPAIGNS['SKIP_VIRUS_CHECK']:
        try:
            host, port = settings.CLAMD_HOST, settings.CLAMD_PORT
        except AttributeError:
            results = dns.resolver.query(settings.CLAMD_SERVICE_NAME, 'SRV')
            servers = [(rr.target.to_text(True), rr.port) for rr in results]
            host, port = servers[0]

        cd = clamd.ClamdNetworkSocket(host=host, port=port)
        check_result, check_msg = cd.instream(afile)['stream']
        # example virus result
        # {'stream': ('FOUND', 'Eicar-Test-Signature')}
        if check_result == 'FOUND':
            raise ValidationError(_(
                'File contains virus: "{}"').format(check_msg))
    return afile 

def get_zone(dns_a_record, config, logger):
    resolv_conf = config.get('resolv_conf')
    if not resolv_conf:
        return None
 
    if os.path.exists(resolv_conf) == False:
        logger.warning("Specified resolv.conf does not exist. Please correct") 
    else:
        try:
            resolver = dns.resolver.Resolver(resolv_conf)
        except Exception as e:
            logger.error("Failed to create a valid Resolver. (error: {0})".format(e))

        dns_zone = dns.resolver.zone_for_name(dns_a_record, resolver=resolver)

    try:
        dns_zone
    except NameError:
        dns_zone = dns.resolver.zone_for_name(dns_a_record)

    return dns_zone 

def run(self, terms, variables=None, **kwargs):

        if HAVE_DNS is False:
            raise AnsibleError("Can't LOOKUP(dnstxt): module dns.resolver is not installed")

        ret = []
        for term in terms:
            domain = term.split()[0]
            string = []
            try:
                answers = dns.resolver.query(domain, 'TXT')
                for rdata in answers:
                    s = rdata.to_text()
                    string.append(s[1:-1])  # Strip outside quotes on TXT rdata

            except dns.resolver.NXDOMAIN:
                string = 'NXDOMAIN'
            except dns.resolver.Timeout:
                string = ''
            except DNSException as e:
                raise AnsibleError("dns.resolver unhandled exception %s" % to_native(e))

            ret.append(''.join(string))

        return ret 

def run(self,thread_cnt=16):
        # ???????,check???????IP??
        all_queue,ok_queue = Queue.Queue(),Queue.Queue()
        for line in self.dict:
            all_queue.put('.'.join([str(line),str(self.target)]))
        
        e_ips,threads = self.resolver.extensive(self.target),[]
        # print '-- extensive',e_ips

        for i in xrange(thread_cnt):
            threads.append(self.bruteWorker(self.resolver,all_queue,ok_queue,e_ips))
        
        for t in threads: t.start()
        for t in threads: t.join()

        while not ok_queue.empty():
            yield ok_queue.get()

    # ??????? 

def getdns(address, arnum):
  addparts = address.split('@')
  hashaddress = hashlib.sha224(addparts[0]).hexdigest()+'._openpgpkey.'+addparts[1]
  #try:
  rlist = dns.resolver.query(hashaddress, arnum)
  print "Rlist:"
  print rlist.rrset
  #except:
  #  print "Not found in DNS: %s" % (hashaddress)
  #  return False

  print "\nAddress:\n"+hashaddress
  for rdata in rlist:
    print "\nData:\n"+str(rdata)+"\n"
    try: something = base64.b64decode(str(rdata))
    except: 
      print "Corrupted data, won't import to gpg keys."
      return False
    stringtofile(something, tempgg)
  rkey = gippy['gpg_import_keys'](tempgg)
  return True



#Confirm that mykey is the one used to verify: 

def import_key(myrecipient, fp, arnum):
    rkey = 0; body = ""
    try:
        addrparts = myrecipient.split('@')
        hashaddress = hashlib.sha224(addrparts[0]).hexdigest()+'._openpgpkey.'+addrparts[1]
        body = "The DNS query string we used to look up your public key is: \n%s\n" % (hashaddress)
        print "DNS query string from %s\nis: %s" % (myrecipient, hashaddress)
        rlist = dns.resolver.query(hashaddress, arnum)
        for rdata in rlist:
            last = str(rdata)
            something = base64.b64decode(str(rdata))
            print "rlist: \n%s\n" % (last)
        rkey = gippy['gpg_import_keys'](something)
        print "Key imported from DNS: %s" % (rkey)
        body += "Key imported from DNS: %s\n" % (rkey)
    except:
        print "Could not import key from DNS into keystore: %s" % (sys.exc_info()[0])
        body = body + "Could not import key from DNS into keystore: %s\n" % (sys.exc_info()[0])
        rkey = 0
    return (rkey, body)

#Store client key in keystore: 

def connect_srv(self, domain=None, keepalive=60, bind_address=""):
        """Connect to a remote broker.

        domain is the DNS domain to search for SRV records; if None,
        try to determine local domain name.
        keepalive and bind_address are as for connect()
        """

        if HAVE_DNS is False:
            raise ValueError('No DNS resolver library found.')

        if domain is None:
            domain = socket.getfqdn()
            domain = domain[domain.find('.') + 1:]

        try:
            rr = '_mqtt._tcp.%s' % domain
            if self._ssl is not None:
                # IANA specifies secure-mqtt (not mqtts) for port 8883
                rr = '_secure-mqtt._tcp.%s' % domain
            answers = []
            for answer in dns.resolver.query(rr, dns.rdatatype.SRV):
                addr = answer.target.to_text()[:-1]
                answers.append((addr, answer.port, answer.priority, answer.weight))
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer, dns.resolver.NoNameservers):
            raise ValueError("No answer/NXDOMAIN for SRV in %s" % (domain))

        # FXME: doesn't account for weight
        for answer in answers:
            host, port, prio, weight = answer

            try:
                return self.connect(host, port, keepalive, bind_address)
            except:
                pass

        raise ValueError("No SRV hosts responded") 

def run(self, domain, record, filename):

        if filename is not None:
            file = open(filename, 'a')
            print("File opened\n"
              "Writing the information on the file..")
            ans = dns.resolver.query(domain, record)
            file.write(ans.response.to_text())
            print("Done.")
            file.close()
        else:
            print('Getting information..')
            ans = dns.resolver.query(domain, record)
            print(ans.response.to_text()) 

def connect_srv(self, domain=None, keepalive=60, bind_address=""):
        """Connect to a remote broker.

        domain is the DNS domain to search for SRV records; if None,
        try to determine local domain name.
        keepalive and bind_address are as for connect()
        """

        if HAVE_DNS is False:
            raise ValueError('No DNS resolver library found.')

        if domain is None:
            domain = socket.getfqdn()
            domain = domain[domain.find('.') + 1:]

        try:
            rr = '_mqtt._tcp.%s' % domain
            if self._ssl is not None:
                # IANA specifies secure-mqtt (not mqtts) for port 8883
                rr = '_secure-mqtt._tcp.%s' % domain
            answers = []
            for answer in dns.resolver.query(rr, dns.rdatatype.SRV):
                addr = answer.target.to_text()[:-1]
                answers.append((addr, answer.port, answer.priority, answer.weight))
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer, dns.resolver.NoNameservers):
            raise ValueError("No answer/NXDOMAIN for SRV in %s" % (domain))

        # FIXME: doesn't account for weight
        for answer in answers:
            host, port, prio, weight = answer

            try:
                return self.connect(host, port, keepalive, bind_address)
            except:
                pass

        raise ValueError("No SRV hosts responded") 

def test_query_nxdomain(self):
        resolver = dns.resolver.Resolver()
        domain = dns.name.from_text('example.com.')

        with unittest.mock.patch.object(resolver, 'query', side_effect=dns.resolver.NXDOMAIN()):
            result = fierce.query(resolver, domain)

        self.assertIsNone(result) 

def test_query_no_nameservers(self):
        resolver = dns.resolver.Resolver()
        domain = dns.name.from_text('example.com.')

        with unittest.mock.patch.object(resolver, 'query', side_effect=dns.resolver.NoNameservers()):
            result = fierce.query(resolver, domain)

        self.assertIsNone(result) 

def connect_srv(self, domain=None, keepalive=60, bind_address=""):
        """Connect to a remote broker.

        domain is the DNS domain to search for SRV records; if None,
        try to determine local domain name.
        keepalive and bind_address are as for connect()
        """

        if HAVE_DNS is False:
            raise ValueError('No DNS resolver library found.')

        if domain is None:
            domain = socket.getfqdn()
            domain = domain[domain.find('.') + 1:]

        try:
            rr = '_mqtt._tcp.%s' % domain
            if self._ssl is not None:
                # IANA specifies secure-mqtt (not mqtts) for port 8883
                rr = '_secure-mqtt._tcp.%s' % domain
            answers = []
            for answer in dns.resolver.query(rr, dns.rdatatype.SRV):
                addr = answer.target.to_text()[:-1]
                answers.append((addr, answer.port, answer.priority, answer.weight))
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer, dns.resolver.NoNameservers):
            raise ValueError("No answer/NXDOMAIN for SRV in %s" % (domain))

        # FIXME: doesn't account for weight
        for answer in answers:
            host, port, prio, weight = answer

            try:
                return self.connect(host, port, keepalive, bind_address)
            except:
                pass

        raise ValueError("No SRV hosts responded") 

def __init__(self, domain, nslist=[], manualip={}, nat={}):
    self.res = dns.resolver.Resolver()
    self.domain = domain
    self.mastername = None
    self.manualip = manualip
    self.nat = nat
    qns = dns.message.make_query(domain+'.', 'NS')
    qns.flags = 0
    self.qns = qns
    if nslist:
      self.setnslist_direct(nslist)
      self.resolve_ips() 

def gen_ips(self):
    """Resolve ips from self.nslist.
    Take manualip and nat tables into account.
    """
    tcp = False
    for fqdn in self.nslist:
      fqdn = fqdn.upper()
      if fqdn in self.manualip:
        yield True, (False, fqdn, self.manualip[fqdn])
        continue
      n = 0
      for t in ['A', 'AAAA']:
        try:
          aip = self.res.query(fqdn, t, tcp=tcp)
        except dns.resolver.NoAnswer:
          continue
        except dns.resolver.NXDOMAIN:
          continue
        except dns.exception.Timeout:
          continue
        except dns.resolver.NoNameservers:
          continue
        iplist = [ip.to_text() for ip in aip.rrset.items]
        natlist = []
        for ip in iplist:
          if ip in self.nat:
            natlist.append(self.nat[ip])
          else:
            natlist.append(ip)
        yield True, (True, fqdn, natlist)
        n += 1
      if n == 0:
        yield None, (None, fqdn, []) 

def get_default_dnsserver():
	default = dns.resolver.get_default_resolver()
	return default.nameservers[0] 

def connect_srv(self, domain=None, keepalive=60, bind_address=""):
        """Connect to a remote broker.

        domain is the DNS domain to search for SRV records; if None,
        try to determine local domain name.
        keepalive and bind_address are as for connect()
        """

        if HAVE_DNS is False:
            raise ValueError('No DNS resolver library found.')

        if domain is None:
            domain = socket.getfqdn()
            domain = domain[domain.find('.') + 1:]

        try:
            rr = '_mqtt._tcp.%s' % domain
            if self._ssl is not None:
                # IANA specifies secure-mqtt (not mqtts) for port 8883
                rr = '_secure-mqtt._tcp.%s' % domain
            answers = []
            for answer in dns.resolver.query(rr, dns.rdatatype.SRV):
                addr = answer.target.to_text()[:-1]
                answers.append((addr, answer.port, answer.priority, answer.weight))
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer, dns.resolver.NoNameservers):
            raise ValueError("No answer/NXDOMAIN for SRV in %s" % (domain))

        # FIXME: doesn't account for weight
        for answer in answers:
            host, port, prio, weight = answer

            try:
                return self.connect(host, port, keepalive, bind_address)
            except:
                pass

        raise ValueError("No SRV hosts responded") 

def validate_existing_mail_domain(email):
    """ Just checks that the associated domain of an email has an MX record.
    """
    if settings.CAMPAIGNS['BYPASS_RECIPIENTS_MX_CHECK']:
        return
    domain = parseaddr(email)[1]

    if domain is None:
        # Trigger no error because email format is supposed to be checked
        # by another validator, needless to report it a second time
        return

    else:
        key = 'domcheck:{}'.format(domain)
        has_error = cache.get(key, None)

        if has_error is None:  # Not present in cache
            try:
                dns.resolver.query(domain, 'MX')
                has_error = False
            except dns.exception.DNSException:
                has_error = True
            finally:
                cache.set(key, has_error, 60)

        if has_error:
            raise ValidationError(_(
                'This domain "{}" doesn\'t seems to be '
                'configured to received emails').format(domain)) 

def _check(peers):

    '''Checks whether the input is a valid list of peers and transforms domain names into IP Addresses'''

    if not isinstance(peers, list):
        return False

    for peer in peers:
        if not isinstance(peer, str):
            return False

    if not HAS_NETADDR:  # if does not have this lib installed, will simply try to load what user specified
        # if the addresses are not correctly specified, will trow error when loading the actual config
        return True

    ip_only_peers = []
    for peer in peers:
        try:
            ip_only_peers.append(str(IPAddress(peer)))  # append the str value
        except AddrFormatError:
            # if not a valid IP Address
            # will try to see if it is a nameserver and resolve it
            if not HAS_DNSRESOLVER:
                continue  # without the dns resolver cannot populate the list of NTP entities based on their nameserver
                # so we'll move on
            dns_reply = []
            try:
                # try to see if it is a valid NS
                dns_reply = dns.resolver.query(peer)
            except dns.resolver.NoAnswer:
                # no a valid DNS entry either
                return False
            for dns_ip in dns_reply:
                ip_only_peers.append(str(dns_ip))

    peers = ip_only_peers

    return True 

def get_iplist(domain=""):       #???????????IP?????iplist
    try:
        A = dns.resolver.query(domain, 'A')  #??A????
    except Exception as e:
        print("dns resolver error:"+str(e))
        return
    for i in A.response.answer:
        for j in i.items:
            iplist.append(j)   #???Iplist
    return True 

def connect_srv(self, domain=None, keepalive=60, bind_address=""):
        """Connect to a remote broker.

        domain is the DNS domain to search for SRV records; if None,
        try to determine local domain name.
        keepalive and bind_address are as for connect()
        """

        if HAVE_DNS is False:
            raise ValueError('No DNS resolver library found, try "pip install dnspython" or "pip3 install dnspython3".')

        if domain is None:
            domain = socket.getfqdn()
            domain = domain[domain.find('.') + 1:]

        try:
            rr = '_mqtt._tcp.%s' % domain
            if self._ssl is not None:
                # IANA specifies secure-mqtt (not mqtts) for port 8883
                rr = '_secure-mqtt._tcp.%s' % domain
            answers = []
            for answer in dns.resolver.query(rr, dns.rdatatype.SRV):
                addr = answer.target.to_text()[:-1]
                answers.append((addr, answer.port, answer.priority, answer.weight))
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer, dns.resolver.NoNameservers):
            raise ValueError("No answer/NXDOMAIN for SRV in %s" % (domain))

        # FIXME: doesn't account for weight
        for answer in answers:
            host, port, prio, weight = answer

            try:
                return self.connect(host, port, keepalive, bind_address)
            except:
                pass

        raise ValueError("No SRV hosts responded") 

def sendannounce(self, server, message):
		tojid = server+"/announce/online"
		jidparams={}
		jidparams['jid'] = self.username+"@"+server
		jidparams['password'] = self.passwd

		jid=xmpp.protocol.JID(jidparams['jid'])

		try:
			r = dns.resolver.query('_xmpp-client._tcp.%s' % server, dns.rdatatype.SRV)
			if len(r)==1:
				server = r[0].target.to_text().rstrip(".")
		except:
			pass

		cl=xmpp.Client(server, debug=[])

		con=cl.connect()
		if not con:
		    print 'could not connect!'
		    sys.exit()
		print 'connected with',con
		auth=cl.auth(jid.getNode(),jidparams['password'],resource=jid.getResource())
		if not auth:
		    print 'could not authenticate!'
		    sys.exit()
		print 'authenticated using',auth

		id=cl.send(xmpp.protocol.Message(tojid,message))
		print 'sent message with id',id 

def connect_srv(self, domain=None, keepalive=60, bind_address=""):
        """Connect to a remote broker.

        domain is the DNS domain to search for SRV records; if None,
        try to determine local domain name.
        keepalive and bind_address are as for connect()
        """

        if HAVE_DNS is False:
            raise ValueError('No DNS resolver library found.')

        if domain is None:
            domain = socket.getfqdn()
            domain = domain[domain.find('.') + 1:]

        try:
            rr = '_mqtt._tcp.%s' % domain
            if self._ssl is not None:
                # IANA specifies secure-mqtt (not mqtts) for port 8883
                rr = '_secure-mqtt._tcp.%s' % domain
            answers = []
            for answer in dns.resolver.query(rr, dns.rdatatype.SRV):
                addr = answer.target.to_text()[:-1]
                answers.append((addr, answer.port, answer.priority, answer.weight))
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer, dns.resolver.NoNameservers):
            raise ValueError("No answer/NXDOMAIN for SRV in %s" % (domain))

        # FIXME: doesn't account for weight
        for answer in answers:
            host, port, prio, weight = answer

            try:
                return self.connect(host, port, keepalive, bind_address)
            except:
                pass

        raise ValueError("No SRV hosts responded") 

def connect_srv(self, domain=None, keepalive=60, bind_address=""):
        """Connect to a remote broker.

        domain is the DNS domain to search for SRV records; if None,
        try to determine local domain name.
        keepalive and bind_address are as for connect()
        """

        if HAVE_DNS is False:
            raise ValueError('No DNS resolver library found, try "pip install dnspython" or "pip3 install dnspython3".')

        if domain is None:
            domain = socket.getfqdn()
            domain = domain[domain.find('.') + 1:]

        try:
            rr = '_mqtt._tcp.%s' % domain
            if self._ssl:
                # IANA specifies secure-mqtt (not mqtts) for port 8883
                rr = '_secure-mqtt._tcp.%s' % domain
            answers = []
            for answer in dns.resolver.query(rr, dns.rdatatype.SRV):
                addr = answer.target.to_text()[:-1]
                answers.append((addr, answer.port, answer.priority, answer.weight))
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer, dns.resolver.NoNameservers):
            raise ValueError("No answer/NXDOMAIN for SRV in %s" % (domain))

        # FIXME: doesn't account for weight
        for answer in answers:
            host, port, prio, weight = answer

            try:
                return self.connect(host, port, keepalive, bind_address)
            except:
                pass

        raise ValueError("No SRV hosts responded") 

def connect_srv(self, domain=None, keepalive=60, bind_address=""):
        """Connect to a remote broker.

        domain is the DNS domain to search for SRV records; if None,
        try to determine local domain name.
        keepalive and bind_address are as for connect()
        """

        if HAVE_DNS is False:
            raise ValueError('No DNS resolver library found.')

        if domain is None:
            domain = socket.getfqdn()
            domain = domain[domain.find('.') + 1:]

        try:
            rr = '_mqtt._tcp.%s' % domain
            if self._ssl is not None:
                # IANA specifies secure-mqtt (not mqtts) for port 8883
                rr = '_secure-mqtt._tcp.%s' % domain
            answers = []
            for answer in dns.resolver.query(rr, dns.rdatatype.SRV):
                addr = answer.target.to_text()[:-1]
                answers.append((addr, answer.port, answer.priority, answer.weight))
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer, dns.resolver.NoNameservers):
            raise ValueError("No answer/NXDOMAIN for SRV in %s" % (domain))

        # FIXME: doesn't account for weight
        for answer in answers:
            host, port, prio, weight = answer

            try:
                return self.connect(host, port, keepalive, bind_address)
            except:
                pass

        raise ValueError("No SRV hosts responded") 

def connect_srv(self, domain=None, keepalive=60, bind_address=""):
        """Connect to a remote broker.

        domain is the DNS domain to search for SRV records; if None,
        try to determine local domain name.
        keepalive and bind_address are as for connect()
        """

        if HAVE_DNS is False:
            raise ValueError('No DNS resolver library found.')

        if domain is None:
            domain = socket.getfqdn()
            domain = domain[domain.find('.') + 1:]

        try:
            rr = '_mqtt._tcp.%s' % domain
            if self._ssl is not None:
                # IANA specifies secure-mqtt (not mqtts) for port 8883
                rr = '_secure-mqtt._tcp.%s' % domain
            answers = []
            for answer in dns.resolver.query(rr, dns.rdatatype.SRV):
                addr = answer.target.to_text()[:-1]
                answers.append((addr, answer.port, answer.priority, answer.weight))
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer, dns.resolver.NoNameservers):
            raise ValueError("No answer/NXDOMAIN for SRV in %s" % (domain))

        # FIXME: doesn't account for weight
        for answer in answers:
            host, port, prio, weight = answer

            try:
                return self.connect(host, port, keepalive, bind_address)
            except:
                pass

        raise ValueError("No SRV hosts responded") 

def setUp(self):
        super(TestDNSServer, self).setUp()
        # Ensure there's an initial DNS publication. Outside of tests this is
        # guaranteed by a migration.
        DNSPublication(source="Initial").save()
        # Allow test-local changes to configuration.
        self.useFixture(RegionConfigurationFixture())
        # Immediately make DNS changes as they're needed.
        self.patch(dns_config_module, "DNS_DEFER_UPDATES", False)
        # Create a DNS server.
        self.bind = self.useFixture(BINDServer())
        # Use the dnspython resolver for at least some queries.
        self.resolver = dns.resolver.Resolver()
        self.resolver.nameservers = ['127.0.0.1']
        self.resolver.port = self.bind.config.port
        patch_dns_config_path(self, self.bind.config.homedir)
        # Use a random port for rndc.
        patch_dns_rndc_port(self, allocate_ports("localhost")[0])
        # This simulates what should happen when the package is
        # installed:
        # Create MAAS-specific DNS configuration files.
        call_command('set_up_dns')
        # Register MAAS-specific DNS configuration files with the
        # system's BIND instance.
        call_command(
            'get_named_conf', edit=True,
            config_path=self.bind.config.conf_file)
        # Reload BIND.
        self.bind.runner.rndc('reload') 

def __init__(self,nameservers=[],timeout=''):
        self.resolver = dns.resolver.Resolver()
        if nameservers: self.resolver.nameservers = nameservers
        if timeout: self.resolver.timeout = timeout
        

    # ??????IP?? 

def query(self,target,rdtype):
        try:
            answer = self.resolver.query(target, rdtype)
            return self.parser(answer)
        except dns.resolver.NoAnswer:
            return None # catch the except, nothing to do
        except dns.resolver.NXDOMAIN:
            return None # catch the except, nothing to do
        except dns.resolver.Timeout:
            # timeout retry
            print(target, rdtype, '<timeout>')
        except Exception, e:
            raise e
            logging.info(str(e)) 

def __init__(self,target,dict_file='top200_domain.txt'):
        self.target = target
        self.dict = list(set(FileUtils.getLines(dict_file)))
        self.resolver = Domain(NAMESERVERS,timeout=5)

    # ????? ?? 

def __init__(self,resolver,all_queue,ok_queue,extensive=[]):
            threading.Thread.__init__(self)
            self.all_queue = all_queue
            self.resolver = resolver
            self.ok_queue = ok_queue
            self.extensive = extensive 

def connect_srv(self, domain=None, keepalive=60, bind_address=""):
        """Connect to a remote broker.

        domain is the DNS domain to search for SRV records; if None,
        try to determine local domain name.
        keepalive and bind_address are as for connect()
        """

        if HAVE_DNS is False:
            raise ValueError('No DNS resolver library found.')

        if domain is None:
            domain = socket.getfqdn()
            domain = domain[domain.find('.') + 1:]

        try:
            rr = '_mqtt._tcp.%s' % domain
            if self._ssl is not None:
                # IANA specifies secure-mqtt (not mqtts) for port 8883
                rr = '_secure-mqtt._tcp.%s' % domain
            answers = []
            for answer in dns.resolver.query(rr, dns.rdatatype.SRV):
                addr = answer.target.to_text()[:-1]
                answers.append((addr, answer.port, answer.priority, answer.weight))
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer, dns.resolver.NoNameservers):
            raise ValueError("No answer/NXDOMAIN for SRV in %s" % (domain))

        # FIXME: doesn't account for weight
        for answer in answers:
            host, port, prio, weight = answer

            try:
                return self.connect(host, port, keepalive, bind_address)
            except:
                pass

        raise ValueError("No SRV hosts responded") 

def get_ip_address_list(domain=""):
    try:
        record_a = dns.resolver.query(domain, 'A')  # A recode type
    except Exception, e:
        print "dns resolver error:" + str(e)
        return
    for i in record_a.response.answer:
        for j in i.items:
            ip_addressList.append(j.address)  # append to ip_addressList
    return True 

def getNameserversForDomain(self,domain="threefoldtoken.org",nameserver="8.8.8.8"):

        resolver = dns.resolver.Resolver(configure=False)
        resolver.nameservers = [nameserver]
        answer = dns.resolver.query(domain, 'NS')

        res=[]
        for rr in answer:
            res.append( rr.target.to_text())
        return res 

def getNameRecordIPs(self,dnsurl="www.threefoldtoken.org",nameserver="8.8.8.8"):
        """
        return ip addr for a full name
        """

        resolver = dns.resolver.Resolver(configure=False)
        resolver.nameservers = [nameserver]
        answer = dns.resolver.query(dnsurl, 'A')

        res=[]
        for rr in answer:
            res.append( rr.address)
        return res 

def dns_wait_soa(self, fqdn, removing=False):
        # Get the serial number for the zone containing the FQDN by asking DNS
        # nicely for the SOA for the FQDN.  If it's top-of-zone, we get an
        # answer, if it's not, we get the SOA in authority.

        if not fqdn.endswith('.'):
            fqdn = fqdn + '.'

        for elapsed, remaining, wait in retries(15, 0.02):
            query_name = fqdn

            # Loop until we have a value for serial, be that numeric or None.
            serial = undefined = object()
            while serial is undefined:
                try:
                    ans = self.resolver.query(
                        query_name, 'SOA', raise_on_no_answer=False)
                except dns.resolver.NXDOMAIN:
                    if removing:
                        # The zone has gone; we're done.
                        return
                    elif "." in query_name:
                        # Query the parent domain for the SOA record.
                        # For most things, this will be the correct DNS zone.
                        # In the case of SRV records, we'll actually need to
                        # strip more, hence the loop.
                        query_name = query_name.split('.', 1)[1]
                    else:
                        # We've hit the root zone; no SOA found.
                        serial = None
                except dns.resolver.NoNameservers:
                    # No DNS service as yet.
                    serial = None
                else:
                    # If we got here, then we either have (1) a situation where
                    # the LHS exists in the DNS, but no SOA RR exists for that
                    # LHS (because it's a node with an A or AAAA RR, and not
                    # the domain...) or (2) an answer to our SOA query.
                    # Either way, we get exactly one SOA in the reply: in the
                    # first case, it's in the Authority section, in the second,
                    # it's in the Answer section.
                    if ans.rrset is None:
                        serial = ans.response.authority[0].items[0].serial
                    else:
                        serial = ans.rrset.items[0].serial

            if serial == DNSPublication.objects.get_most_recent().serial:
                # The zone is up-to-date; we're done.
                return
            else:
                time.sleep(wait)

        self.fail("Timed-out waiting for %s to update." % fqdn)