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NSLOOKUP returns multiple DNS names for one IP

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  • NSLOOKUP returns multiple DNS names for one IP

    Each time I run this NSLOOKUP, irrespective of which machine I run it on, I get the following result:

    Code:
    > set debug
    > 10.125.5.20
    Server:  UnKnown
    Address:  ::1
    
    ------------
    Got answer:
        HEADER:
            opcode = QUERY, id = 4, rcode = NOERROR
            header flags:  response, auth. answer, want recursion, recursion avail.
            questions = 1,  answers = 3,  authority records = 0,  additional = 0
    
        QUESTIONS:
            20.5.125.10.in-addr.arpa, type = PTR, class = IN
        ANSWERS:
        ->  20.5.125.10.in-addr.arpa
            name = ipmgmt-uat.au.au.MyDomain.com
            ttl = 3600 (1 hour)
        ->  20.5.125.10.in-addr.arpa
            name = au-l387.MyDomain.com
            ttl = 900 (15 mins)
        ->  20.5.125.10.in-addr.arpa
            name = au-l598.MyDomain.com
            ttl = 900 (15 mins)
    
    ------------
    Name:    ipmgmt-uat.au.au.MyDomain.com
    Address:  10.125.5.20
    
    >
    Why is NSLOOKUP returning three different machine DNS names for the one IP??

    I've checked the DNS servers and DHCP servers and cannot find a reason for this.

    Thanks.
    |
    +-- JDMils
    |
    +-- Regional Systems Engineer, DotNet programmer & Jack of all trades
    |

  • #2
    Re: NSLOOKUP returns multiple DNS names for one IP

    There must be two PTR records for that ip address. Did you check the reverse lookup zone seeing as that's what you're querying for? (an ip address to DNS name resolution)

    Comment


    • #3
      Re: NSLOOKUP returns multiple DNS names for one IP

      I count 3 PTR records.

      This is totally feasible that there are multiple PTR records. It is usually someone leaving the check box to create the pointer record when creating an A record. It could also be from DHCP server/clients not cleaning up properly after they're done with an IP address.
      Regards,
      Jeremy

      Network Consultant/Engineer
      Baltimore - Washington area and beyond
      www.gma-cpa.com

      Comment


      • #4
        Re: NSLOOKUP returns multiple DNS names for one IP

        Spot On JoeQwerty & Jeremy! I've deleted the reverse lookup IPs and the NSLOOKUP now returns nothing. Which was foreseen as I am waiting for the user to restart their workstation in order to re-register their DNS. (I know they can IPCONFIG /REGISTERDNS...... I just like to be sure and ask the users to restart their machines)!

        Thanks again!
        |
        +-- JDMils
        |
        +-- Regional Systems Engineer, DotNet programmer & Jack of all trades
        |

        Comment


        • #5
          Re: NSLOOKUP returns multiple DNS names for one IP

          Glad to help.

          Comment

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