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    DNS lokup adding dmain name

    Scheduled Pinned Locked Moved DHCP and DNS
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    • P
      PeterK2003
      last edited by

      Why when i do an nslookup on google.com is it returning with google.com.mydomain.com?

      Let me know what other info you need.

      Thanks,
      Peter

      1 Reply Last reply Reply Quote 0
      • johnpozJ
        johnpoz LAYER 8 Global Moderator
        last edited by

        that is a client setting to append search domains.

        could you post the output of your nslookup

        You normally would not see that unless you set debug, if you don't want it to happen you can end your host entry with .

        So for example here is query for google.com, notice return the answer – but if I set debug, see how it asked for both the A and AAAA records with my local.lan domain attached.

        
        C:\>nslookup
        Default Server:  pfsense.local.lan
        Address:  192.168.1.253
        
        > google.com
        Server:  pfsense.local.lan
        Address:  192.168.1.253
        
        Non-authoritative answer:
        Name:    google.com
        Addresses:  74.125.225.82
                  74.125.225.81
                  74.125.225.84
                  74.125.225.80
                  74.125.225.83
        
        > set debug
        > google.com
        Server:  pfsense.local.lan
        Address:  192.168.1.253
        
        ------------
        Got answer:
            HEADER:
                opcode = QUERY, id = 6, rcode = NXDOMAIN
                header flags:  response, want recursion, recursion avail.
                questions = 1,  answers = 0,  authority records = 1,  additional = 0
        
            QUESTIONS:
                google.com.local.lan, type = A, class = IN
            AUTHORITY RECORDS:
            ->  (root)
                ttl = 86261 (23 hours 57 mins 41 secs)
                primary name server = a.root-servers.net
                responsible mail addr = nstld.verisign-grs.com
                serial  = 2011110701
                refresh = 1800 (30 mins)
                retry   = 900 (15 mins)
                expire  = 604800 (7 days)
                default TTL = 86400 (1 day)
        
        ------------
        ------------
        Got answer:
            HEADER:
                opcode = QUERY, id = 7, rcode = NXDOMAIN
                header flags:  response, want recursion, recursion avail.
                questions = 1,  answers = 0,  authority records = 1,  additional = 0
        
            QUESTIONS:
                google.com.local.lan, type = AAAA, class = IN
            AUTHORITY RECORDS:
            ->  (root)
                ttl = 86261 (23 hours 57 mins 41 secs)
                primary name server = a.root-servers.net
                responsible mail addr = nstld.verisign-grs.com
                serial  = 2011110701
                refresh = 1800 (30 mins)
                retry   = 900 (15 mins)
                expire  = 604800 (7 days)
                default TTL = 86400 (1 day)
        
        ------------
        ------------
        Got answer:
            HEADER:
                opcode = QUERY, id = 8, rcode = NOERROR
                header flags:  response, want recursion, recursion avail.
                questions = 1,  answers = 5,  authority records = 0,  additional = 0
        
            QUESTIONS:
                google.com, type = A, class = IN
            ANSWERS:
            ->  google.com
                internet address = 74.125.225.82
                ttl = 161 (2 mins 41 secs)
            ->  google.com
                internet address = 74.125.225.81
                ttl = 161 (2 mins 41 secs)
            ->  google.com
                internet address = 74.125.225.84
                ttl = 161 (2 mins 41 secs)
            ->  google.com
                internet address = 74.125.225.80
                ttl = 161 (2 mins 41 secs)
            ->  google.com
                internet address = 74.125.225.83
                ttl = 161 (2 mins 41 secs)
        
        ------------
        Non-authoritative answer:
        ------------
        Got answer:
            HEADER:
                opcode = QUERY, id = 9, rcode = NOERROR
                header flags:  response, want recursion, recursion avail.
                questions = 1,  answers = 0,  authority records = 1,  additional = 0
        
            QUESTIONS:
                google.com, type = AAAA, class = IN
            AUTHORITY RECORDS:
            ->  google.com
                ttl = 474 (7 mins 54 secs)
                primary name server = ns1.google.com
                responsible mail addr = dns-admin.google.com
                serial  = 1467440
                refresh = 7200 (2 hours)
                retry   = 1800 (30 mins)
                expire  = 1209600 (14 days)
                default TTL = 300 (5 mins)
        
        ------------
        Name:    google.com
        Addresses:  74.125.225.82
                  74.125.225.81
                  74.125.225.84
                  74.125.225.80
                  74.125.225.83
        
        >
        
        

        If use . on the end like google.com. then it doesn't do that

        
        C:\>nslookup
        Default Server:  pfsense.local.lan
        Address:  192.168.1.253
        
        > google.com.
        Server:  pfsense.local.lan
        Address:  192.168.1.253
        
        Non-authoritative answer:
        Name:    google.com
        Addresses:  74.125.225.83
                  74.125.225.84
                  74.125.225.81
                  74.125.225.82
                  74.125.225.80
        
        > set debug
        > google.com.
        Server:  pfsense.local.lan
        Address:  192.168.1.253
        
        ------------
        Got answer:
            HEADER:
                opcode = QUERY, id = 4, rcode = NOERROR
                header flags:  response, want recursion, recursion avail.
                questions = 1,  answers = 5,  authority records = 0,  additional = 0
        
            QUESTIONS:
                google.com, type = A, class = IN
            ANSWERS:
            ->  google.com
                internet address = 74.125.225.83
                ttl = 291 (4 mins 51 secs)
            ->  google.com
                internet address = 74.125.225.84
                ttl = 291 (4 mins 51 secs)
            ->  google.com
                internet address = 74.125.225.81
                ttl = 291 (4 mins 51 secs)
            ->  google.com
                internet address = 74.125.225.82
                ttl = 291 (4 mins 51 secs)
            ->  google.com
                internet address = 74.125.225.80
                ttl = 291 (4 mins 51 secs)
        
        ------------
        Non-authoritative answer:
        ------------
        Got answer:
            HEADER:
                opcode = QUERY, id = 5, rcode = NOERROR
                header flags:  response, want recursion, recursion avail.
                questions = 1,  answers = 0,  authority records = 1,  additional = 0
        
            QUESTIONS:
                google.com, type = AAAA, class = IN
            AUTHORITY RECORDS:
            ->  google.com
                ttl = 428 (7 mins 8 secs)
                primary name server = ns1.google.com
                responsible mail addr = dns-admin.google.com
                serial  = 1467441
                refresh = 7200 (2 hours)
                retry   = 1800 (30 mins)
                expire  = 1209600 (14 days)
                default TTL = 300 (5 mins)
        
        ------------
        Name:    google.com
        Addresses:  74.125.225.83
                  74.125.225.84
                  74.125.225.81
                  74.125.225.82
                  74.125.225.80
        
        >
        
        

        Now you could turn off the use of search suffixes, but then would not allow you to do a dns query via just host name, like so

        
        C:\>nslookup
        Default Server:  pfsense.local.lan
        Address:  192.168.1.253
        
        > p4-28g
        Server:  pfsense.local.lan
        Address:  192.168.1.253
        
        Name:    p4-28g.local.lan
        Address:  192.168.1.4
        
        > set debug
        > p4-28g
        Server:  pfsense.local.lan
        Address:  192.168.1.253
        
        ------------
        Got answer:
            HEADER:
                opcode = QUERY, id = 4, rcode = NOERROR
                header flags:  response, auth. answer, want recursion, recursion avail.
                questions = 1,  answers = 1,  authority records = 0,  additional = 0
        
            QUESTIONS:
                p4-28g.local.lan, type = A, class = IN
            ANSWERS:
            ->  p4-28g.local.lan
                internet address = 192.168.1.4
                ttl = 3600 (1 hour)
        
        ------------
        ------------
        Got answer:
            HEADER:
                opcode = QUERY, id = 5, rcode = NOERROR
                header flags:  response, auth. answer, want recursion, recursion avail.
                questions = 1,  answers = 0,  authority records = 0,  additional = 0
        
            QUESTIONS:
                p4-28g.local.lan, type = AAAA, class = IN
        
        ------------
        Name:    p4-28g.local.lan
        Address:  192.168.1.4
        
        

        See how it auto added my local.lan to the search

        Now there is a group policy or reg key you can set to turn this control this functionality atleast for users of the dnsclient, like ping and browser, etc.  But nslookup is not effected – if you do not want nslookup to use your suffix and or search suffixes, etc. then just end the query with . like in my above example.

        Here is info on that reg key entry
        http://blogs.technet.com/b/networking/archive/2009/04/16/dns-client-name-resolution-behavior-in-windows-vista-vs-windows-xp.aspx
        DNS Client Name Resolution behavior in Windows Vista vs. Windows XP

        HKLM\Software\Policies\Microsoft\Windows NT\DNSClient\AppendToMultiLabelName

        Hope that helps!

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        • jimpJ
          jimp Rebel Alliance Developer Netgate
          last edited by

          That happens most often when your domain has wildcard DNS active.

          The way DNS works, as laid out above, your search domain is appended before it queries farther up. Because you have wildcard DNS on, that returns a valid response.

          Without wildcard DNS, the entry does not exist, and it moves on to trying a higher level.

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