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DHCP clients taking DNS settings of ISP instead of router

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  • DHCP clients taking DNS settings of ISP instead of router

    I have 3x desktops, two running WinXP SP3 (JDMILS & SPARE01) and another running Win2K3 (DOWNLOADS), a NAS device (STORAGE-4CA5) and a notebook on wireless running WinXP SP3 (COMPAQ9110).

    From the notebook (COMPAQ9110) I can ping one wired XP desktop (JDMILS), the NAS and the wired Win2K3 server (DOWNLOADS) but not the WinXP desktop (SPARE01).

    My router (Netgear DG834G) is showing the following devices attached:

    Code:
    #  	 IP Address   	 Device Name   	 MAC Address
    1 	192.168.100.2 	STORAGE-4CA5 	00:14:3F:A0:4C:A5
    2 	192.168.100.5 	JDMILS 	00:1A:4D:5A:05:7E
    3 	192.168.100.10 	UNKNOWN 	00:C0:02:A5:A5:07
    4 	192.168.100.12 	DOWNLOADS 	00:48:54:56:4B:49
    5 	192.168.100.100 	UNKNOWN 	00:11:2F:2E:63:CF
    6 	192.168.100.112 	COMPAQNX9110 	00:90:4B:57:2A:CC


    Here is the IPCONFIG of the notebook:

    Code:
    C:\Documents and Settings\Julian>ipconfig /all
    
    Windows IP Configuration
    
            Host Name . . . . . . . . . . . . : compaqnx9110
            Primary Dns Suffix  . . . . . . . :
            Node Type . . . . . . . . . . . . : Unknown
            IP Routing Enabled. . . . . . . . : No
            WINS Proxy Enabled. . . . . . . . : No
    
    Ethernet adapter Local Area Connection:
    
            Media State . . . . . . . . . . . : Media disconnected
            Description . . . . . . . . . . . : Realtek RTL8139/810x Family Fast Ethernet NIC
            Physical Address. . . . . . . . . : 00-02-3F-22-A4-83
    
    Ethernet adapter Wireless Network Connection:
    
            Connection-specific DNS Suffix  . :
            Description . . . . . . . . . . . : Broadcom 802.11b
            Physical Address. . . . . . . . . : 00-90-4B-57-2A-CC
            Dhcp Enabled. . . . . . . . . . . : Yes
            Autoconfiguration Enabled . . . . : Yes
            IP Address. . . . . . . . . . . . : 192.168.100.112
            Subnet Mask . . . . . . . . . . . : 255.255.255.0
            Default Gateway . . . . . . . . . : 192.168.100.1
            DHCP Server . . . . . . . . . . . : 192.168.100.1
            DNS Servers . . . . . . . . . . . : 203.12.160.35
                                                203.12.160.36
            Lease Obtained. . . . . . . . . . : Tuesday, 6 January 2009 10:31:51 PM
            Lease Expires . . . . . . . . . . : Wednesday, 7 January 2009 10:31:51 PM


    Notice the DNS? It's the DNS of my ISP!? With my previous ISP (Datafast), the DNS and gateway addresses were always set automatically to the router but with my new ISP it is now pointing to the ISP's DNS servers. I can't find anywhere on the router where I can set the DNS & gateway of the DHCP clients. Is this normal?

    Also, here's the output of an NSLOOKUP:

    Code:
    C:\Documents and Settings\Julian>nslookup jdmils
    Server:  dns1.tpgi.com.au
    Address:  203.12.160.35
    
    *** dns1.tpgi.com.au can't find jdmils: Non-existent domain
    
    C:\Documents and Settings\Julian>ping jdmils
    
    Pinging jdmils [192.168.100.5] with 32 bytes of data:
    
    Reply from 192.168.100.5: bytes=32 time=1ms TTL=128
    Reply from 192.168.100.5: bytes=32 time=1ms TTL=128
    Reply from 192.168.100.5: bytes=32 time=1ms TTL=128
    Reply from 192.168.100.5: bytes=32 time=1ms TTL=128
    
    Ping statistics for 192.168.100.5:
        Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
    Approximate round trip times in milli-seconds:
        Minimum = 1ms, Maximum = 1ms, Average = 1ms
    
    C:\Documents and Settings\Julian>


    Note the NSLOOKUP doesn't provide a result but the ping still works? Can anyone explain why this is happening? How do I fix this?

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

  • #2
    Re: DHCP clients taking DNS settings of ISP instead of router

    Originally posted by JDMils View Post
    I can't find anywhere on the router where I can set the DNS & gateway of the DHCP clients. Is this normal?
    DNS is under Setup > Basic Settings. The gateway address is hardcoded as the address of the router.

    If you have a second NIC in your 2k3 box, you could setup DNS, DHCP and RRaS on there, and use that as the gateway for your LAN - just connect the router to the server's 2nd NIC.
    Gareth Howells

    BSc (Hons), MBCS, MCP, MCDST, ICCE

    Any advice is given in good faith and without warranty.

    Please give reputation points if somebody has helped you.

    "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

    "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

    Comment


    • #3
      Re: DHCP clients taking DNS settings of ISP instead of router

      I think that's normal for Netgear (as well as Linksys) routers. I believe there's an option in the router to enter your own DNS servers, but as far as I remember from the Netgear routers I've had, the DNS servers are "passed through" from the ISP to the clients by the router.

      Comment


      • #4
        Re: DHCP clients taking DNS settings of ISP instead of router

        By default, yes. However the DNS entries under Basic Settings allow you to specify the IPs of the DNS servers to use.
        Gareth Howells

        BSc (Hons), MBCS, MCP, MCDST, ICCE

        Any advice is given in good faith and without warranty.

        Please give reputation points if somebody has helped you.

        "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

        "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

        Comment


        • #5
          Re: DHCP clients taking DNS settings of ISP instead of router

          Exactly, which is what I do at home. I then plug in the DNS servers from OpenDNS.

          Comment


          • #6
            Re: DHCP clients taking DNS settings of ISP instead of router

            Guys, the DNS servers under Basic Settings are the DNS servers for the ISP, not for DHCP.

            The router "used to" provide the DNS & Gateway of its own IP to the DHCP clients, but it seems that when I reprogrammed/reset the router for the new ISP settings, it now relays the ISP's DNS settings to the DHCP clients. It still sets the gateway to the router for the clients tho.

            Looks like the only resolve is to set DNS static in each client to the router's address. is this all I have left to do (other than create my own DNS server)?
            |
            +-- JDMils
            |
            +-- Regional Systems Engineer, DotNet programmer & Jack of all trades
            |

            Comment


            • #7
              Re: DHCP clients taking DNS settings of ISP instead of router

              How is DHCP setup on you router???

              What type of router is it??

              Comment


              • #8
                Re: DHCP clients taking DNS settings of ISP instead of router

                Personally I'd disable DHCP on the router and have the server do it. Setup DNS with forwarders to the ISPs DNS servers and use DHCP to allocate only the local DNS server to the clients.

                My sister has a DG834G (actually a DG834GT, Sky firmware) and there is no option in it to set a local DNS server that I can find.
                BSc, MCSA: Server 2008, MCSE, MCSA: Messaging, MCTS
                sigpic
                Cruachan's Blog

                Comment


                • #9
                  Re: DHCP clients taking DNS settings of ISP instead of router

                  Originally posted by cruachan View Post
                  Personally I'd disable DHCP on the router and have the server do it.
                  Sorry, this is a home network and there are no servers. I suppose you are saying that DNS on a server is the only way? Thanks.
                  |
                  +-- JDMils
                  |
                  +-- Regional Systems Engineer, DotNet programmer & Jack of all trades
                  |

                  Comment


                  • #10
                    Re: DHCP clients taking DNS settings of ISP instead of router

                    You said you were running Server 2003 on a machine, now you're saying there are no servers...
                    Gareth Howells

                    BSc (Hons), MBCS, MCP, MCDST, ICCE

                    Any advice is given in good faith and without warranty.

                    Please give reputation points if somebody has helped you.

                    "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

                    "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

                    Comment


                    • #11
                      Re: DHCP clients taking DNS settings of ISP instead of router

                      As gforce said, your first post indicates one of your desktops is running Windows 2K3 which is a server operating system.
                      BSc, MCSA: Server 2008, MCSE, MCSA: Messaging, MCTS
                      sigpic
                      Cruachan's Blog

                      Comment


                      • #12
                        Re: DHCP clients taking DNS settings of ISP instead of router

                        Very sorry about that. The 2003 machine is a test machine which is only running when I need to test a VB.Net app on server 2003 OS environment.
                        |
                        +-- JDMils
                        |
                        +-- Regional Systems Engineer, DotNet programmer & Jack of all trades
                        |

                        Comment


                        • #13
                          Re: DHCP clients taking DNS settings of ISP instead of router

                          Ok. To answer your original question, yes it is perfectly normal for the router to assign your ISP's DNS server address to DHCP clients. Not all routers have a DNS server built into them - in this case, your router does not.
                          Gareth Howells

                          BSc (Hons), MBCS, MCP, MCDST, ICCE

                          Any advice is given in good faith and without warranty.

                          Please give reputation points if somebody has helped you.

                          "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

                          "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

                          Comment


                          • #14
                            Re: DHCP clients taking DNS settings of ISP instead of router

                            Did you enter the TPG DNS into the Router as static entries (Use These DNS Servers) or have you set the Get Automatically From ISP option? This is under Basic Settings in the Router. You may have to scroll down, depending on your resolution.
                            1 1 was a racehorse.
                            2 2 was 1 2.
                            1 1 1 1 race 1 day,
                            2 2 1 1 2

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