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Heads up - network issues after boot!

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  • Heads up - network issues after boot!

    Seemingly randomly, Windows Server 2003 will sometimes lose network connectivity after boot. The NIC is working, you can see you have Layer 2 connectivity because the lights are flashing.... but if you try to ping anything except the local address or 127.0.0.1 you get "Destination Host Unreachable".

    There are two causes for this that I have found; (the second) one of which I have since found out has a Microsoft article associated with it.

    1/ Windows Firewall/ICS Service. Despite the firewall being unticked on all network adapters, and no filtering rules applied anyway, if the Windows Firewall Service is running, you may encounter this issue; the firewall is blocking even though it is disabled. The only way to make the server work again is to "disable" the "Windows Firewall/ICS Service" and reboot the server.

    2/ IPSEC Services. Despite IPSEC not being enabled on any adapter, if the IPSEC service is running but no IP filtering is set, the IPSEC service will have all network connectivity blocked by putting the NICs in "lockdown" mode. The only way to stop this is to disable the IPSEC service and reboot the machine.

    As we never use the IPSEC or Firewall/ICS services on our machines, I routinely stop and disable both of these services while I am working on a server. That way I am maximising the chances of the server coming back up on the network following a reboot!!


    Tom
    For my own and your protection, I do not provide support by private message under any circumstances. All such messages will be deleted and ignored.

    Anything you say will be misquoted and used against you

  • #2
    Re: Heads up - network issues after boot!

    p.s. I couldn't find the MS article about my second point... sorry! Will try to find tomorrow.


    Tom
    For my own and your protection, I do not provide support by private message under any circumstances. All such messages will be deleted and ignored.

    Anything you say will be misquoted and used against you

    Comment


    • #3
      Re: Heads up - network issues after boot!

      Interesting. I always thought (and confirmed in a few tests, if I remember correctly) that disabling the IPSEC service would cause a loss of connectivity because even if there are no IPSEC policies the service still needs to process "no policies". I could be wrong.

      Comment


      • #4
        Re: Heads up - network issues after boot!

        Well I just tested it on a Windows 2003 SP2 box and disabling the IPSEC service does not appear to affect network connectivity. I could swear I ran into this before...

        Comment


        • #5
          Re: Heads up - network issues after boot!

          Originally posted by Stonelaughter View Post
          Seemingly randomly, Windows Server 2003 will sometimes lose network connectivity after boot.
          Any idea if this may be dependant on the network adapter you have installed? In other words, is this something else we can blame on Broadcom?
          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.

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          • #6
            Re: Heads up - network issues after boot!

            Nope... it occurs at Layer 3 and above; therefore this one's ALL Microsoft


            Tom
            For my own and your protection, I do not provide support by private message under any circumstances. All such messages will be deleted and ignored.

            Anything you say will be misquoted and used against you

            Comment


            • #7
              Re: Heads up - network issues after boot!

              Probably already done but have you reset TCP/IP and Winsock on the server???

              netsh int ip reset c:\resetlog.txt will reset your TCP/IP Stack.

              netsh winsock reset will reset winsock.

              Comment


              • #8
                Re: Heads up - network issues after boot!

                Possibly could be the NIC? The IP address used will look in the ARP cache to enable the communiation with the remote server's NIC and of course for travelling across the network. Just a thought.

                I had a weird problem and still do. I have some Dell switches that are ok with Intel NICs. I got a new machine with another NIC type and it was showing status as disconnected. I thought it was a hardware fault. I changed the speed to a manual 10 Mbps as it wouldn't with 100 or auto setting, and problem resolved. It has happened to other machines. However, Intel works at 100 Mbps. By the way, this is not hijacking the thread, just an example. I will post separately at some point when I have time to look in to it further.

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                • #9
                  Re: Heads up - network issues after boot!

                  Ummm.... ARP is at layer 2 and NIC is at layer 1... this problem occurs at layer 3. I have layer 2 connectivity... just no layer 3. (i.e. TCP).


                  Tom
                  For my own and your protection, I do not provide support by private message under any circumstances. All such messages will be deleted and ignored.

                  Anything you say will be misquoted and used against you

                  Comment


                  • #10
                    Re: Heads up - network issues after boot!

                    It could be a driver issue.
                    Anything in the loggings or within a sniffertrace during boot (with a span port or so)??
                    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"

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                    • #11
                      Re: Heads up - network issues after boot!

                      Originally posted by Stonelaughter View Post
                      just no layer 3. (i.e. TCP).
                      I think TCP is L4 as it runs over IP on L3?
                      cheers
                      Andy

                      Please read this before you post:


                      Quis custodiet ipsos custodes?

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                      • #12
                        Re: Heads up - network issues after boot!

                        My mistake - you're right of course.


                        Tom
                        For my own and your protection, I do not provide support by private message under any circumstances. All such messages will be deleted and ignored.

                        Anything you say will be misquoted and used against you

                        Comment


                        • #13
                          Re: Heads up - network issues after boot!

                          Originally posted by Stonelaughter View Post
                          Ummm.... ARP is at layer 2 and NIC is at layer 1... this problem occurs at layer 3. I have layer 2 connectivity... just no layer 3. (i.e. TCP).
                          Certainly is a strange one. I realise IP is layer 3 but in order for you to ping the local host, the packet will need to use layer 1 and 2 to make it to the host. Have you tried reinstalling the driver?

                          Comment


                          • #14
                            Re: Heads up - network issues after boot!

                            Just to clarify:

                            In the OSI Network Model TCP is at layer 4 and IP is at layer 3
                            In the TCP/IP Network Model TCP is at layer 3 and IP is at layer 2

                            When discussing networking, the OSI Network Model is usually used as the reference when discussing what components reside at which layer.

                            http://en.wikipedia.org/wiki/OSI_Reference_Model

                            http://en.wikipedia.org/wiki/TCP/IP_model

                            Comment


                            • #15
                              Re: Heads up - network issues after boot!

                              I agree Joe. The OSI model is the assumed one. IP at layer 3, MAC adresses at layer 2 and then the bits (0's and 1's) that travel down te physical cable.

                              NIC is at layer 2 and of course the IP routing at layer 3.

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