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Multihomed server looses all network connection when the second card is attached

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  • Multihomed server looses all network connection when the second card is attached

    Hi there, hope someone can help with this problem - I've probably missed something simple!!

    I've got a Windows Server 2003 (not a DC) which runs our backups. We've recently moved it to a new VLAN and given it a new IP. The swapover seems to be fine but the backups to the old VLAN are now quite slow so I want to take advantage of a second NIC to provide a connection to the old VLAN so that traffic doesn't have to go through the router. However, when I plug in the second network cable, the machine looses all network connectivity through the new IP - as this machine is also our primary fileserver this is a bit of a problem!

    The details:
    NIC#1: (the new VLAN)
    IP: 172.28.0.19
    Subnet: 255.255.252.0
    Gateway: 172.28.3.254
    DNS1: 172.28.0.10
    DNS2: 172.18.8.10

    NIC#2: (the old VLAN)
    IP: 172.18.8.21
    Subnet: 255.255.255.0
    Gateway: <blank>
    DNS1: <blank>
    DNS2: <blank>

    Any ideas why plugging in NIC#2 disables access via NIC#1?

  • #2
    Re: Multihomed server looses all network connection when the second card is attached

    Any static routes in place?
    Marcel
    Technical Consultant
    Netherlands
    http://www.phetios.com
    http://blog.nessus.nl

    MCITP(EA, SA), MCSA/E 2003:Security, CCNA, SNAF, DCUCI, CCSA/E/E+ (R60), VCP4/5, NCDA, NCIE - SAN, NCIE - BR, EMCPE
    "No matter how secure, there is always the human factor."

    "Enjoy life today, tomorrow may never come."
    "If you're going through hell, keep going. ~Winston Churchill"

    Comment


    • #3
      Re: Multihomed server looses all network connection when the second card is attached

      Originally posted by Dumber View Post
      Any static routes in place?
      Not to my knowledge...

      Comment


      • #4
        Re: Multihomed server looses all network connection when the second card is attached

        if RRAS is running, check RRAS first.
        Second either if RRAS is running or not, check with the route print command for any routes.
        Ps. I think you need to add a gateway or a route to find the other networks via the second nic.
        Marcel
        Technical Consultant
        Netherlands
        http://www.phetios.com
        http://blog.nessus.nl

        MCITP(EA, SA), MCSA/E 2003:Security, CCNA, SNAF, DCUCI, CCSA/E/E+ (R60), VCP4/5, NCDA, NCIE - SAN, NCIE - BR, EMCPE
        "No matter how secure, there is always the human factor."

        "Enjoy life today, tomorrow may never come."
        "If you're going through hell, keep going. ~Winston Churchill"

        Comment


        • #5
          Re: Multihomed server looses all network connection when the second card is attached

          RAAS isn't installed

          "route print " gives:
          Code:
          IPv4 Route Table
          ===========================================================================
          Interface List
          0x1 ........................... MS TCP Loopback interface
          0x10003 ...00 18 8b 76 c8 a3 ...... Broadcom BCM5708C NetXtreme II GigE (NDIS VB
          D Client)
          0x10004 ...00 18 8b 76 c8 a5 ...... Broadcom BCM5708C NetXtreme II GigE (NDIS VB
          D Client) #2
          ===========================================================================
          ===========================================================================
          Active Routes:
          Network Destination        Netmask          Gateway       Interface  Metric
                    0.0.0.0          0.0.0.0     172.28.3.254      172.28.0.19     10
                  127.0.0.0        255.0.0.0        127.0.0.1        127.0.0.1      1
                 172.28.0.0    255.255.252.0      172.28.0.19      172.28.0.19     10
                172.28.0.19  255.255.255.255        127.0.0.1        127.0.0.1     10
             172.28.255.255  255.255.255.255      172.28.0.19      172.28.0.19     10
                  224.0.0.0        240.0.0.0      172.28.0.19      172.28.0.19     10
            255.255.255.255  255.255.255.255      172.28.0.19            10004      1
            255.255.255.255  255.255.255.255      172.28.0.19      172.28.0.19      1
          Default Gateway:      172.28.3.254
          ===========================================================================
          Persistent Routes:
            None
          I tried adding a default gateway to NIC#2 but got the message:
          Warning - Multiple default gateways are intended to provide redundancy to a single network (such as an intranet or the Internet). They will not function properly when the gateways are on two separate, disjoint networks (such as one on your intranet and one on the Internet). Do you want to save this configuration? Yes/No

          I have tried both options!

          For reference, most of the client machines are on the 172.18.0.* VLAN...

          Comment


          • #6
            Re: Multihomed server looses all network connection when the second card is attached

            you have to remove the default gateway from the other nic first.
            Marcel
            Technical Consultant
            Netherlands
            http://www.phetios.com
            http://blog.nessus.nl

            MCITP(EA, SA), MCSA/E 2003:Security, CCNA, SNAF, DCUCI, CCSA/E/E+ (R60), VCP4/5, NCDA, NCIE - SAN, NCIE - BR, EMCPE
            "No matter how secure, there is always the human factor."

            "Enjoy life today, tomorrow may never come."
            "If you're going through hell, keep going. ~Winston Churchill"

            Comment

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