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  • Client computers cannot access Internet following ISP change

    Hello all

    This is my first post here although I have found many answers here before!

    Ok here goes. I have spent all day trying to solve an issue for a friend, they have changed ISPs and repogrammed the router and SBS2003 server with new IP addresses etc.

    The setup is Router - SBS WAN NIC - SBS LAN NIC - HUB - PC's

    Basically the Server can access the internet, you can access websites etc from the server. The server is receiving email and email is being received on the client PCs, they can also send email. THe issue is the PCs can no longer access the internet! If I try to ping anything the address resolves however we get a reply from the server LAN NIC destination unreachable. I can however ping all of these addresses from the server.

    All they changed (as far as i know) was the IP Addresses on the WAN NIC which is what is really puzzling me.

    To me (and i am not that clued up on these things) it appears that the lan and wan nics are not communicating correctly.

    Any ideas? Please help

    Anthony

  • #2
    Re: Client computers cannot access Internet following ISP change

    An ICMP destination unreachable message could be the result of several different things, but most likely it's a routing issue between the LAN and WAN interfaces on the server.

    It looks to me like the LAN clients use the server as their default gateway, is that correct? If so then you're probably running ICS on the server, is that correct? Check the default gateway settings on the client and server and make sure they're correct. Check the ICS configuration to see if it's needs to be modified as a result of the new WAN ip address on the server.

    The other thing you can do is install Microsoft Network Monitor 3 on the LAN client, start a capture, ping www.google.com, filter the capture for ICMP, and tell us what type and code values are in the ICMP destination unreachable messages. This will tell us exactly why the pings are failing.

    Comment


    • #3
      Re: Client computers cannot access Internet following ISP change

      Originally posted by joeqwerty View Post
      An ICMP destination unreachable message could be the result of several different things, but most likely it's a routing issue between the LAN and WAN interfaces on the server.
      Thanks Joe, that is what it looks to be to me

      Originally posted by joeqwerty View Post
      It looks to me like the LAN clients use the server as their default gateway, is that correct? If so then you're probably running ICS on the server, is that correct? Check the default gateway settings on the client and server and make sure they're correct. Check the ICS configuration to see if it's needs to be modified as a result of the new WAN ip address on the server.
      You will have to bare with me a little on this, yes the clients use the server as their gateway, the gateway on the clients is 192.168.0.2 which is the LAN NIC, the server is (or at least should be DHCP'ing!!). Could you please talk me through checking the ICS settings on the server? I can access it remotely but am not sure where I need be looking. I am almost certain these will not have been changed so you may have hit the nail on the head


      Originally posted by joeqwerty View Post
      The other thing you can do is install Microsoft Network Monitor 3 on the LAN client, start a capture, ping www.google.com, filter the capture for ICMP, and tell us what type and code values are in the ICMP destination unreachable messages. This will tell us exactly why the pings are failing.
      Ok.. well if he ICS doesnt resolve this I will try this! Am hoping its straitforward?

      Thanks
      A

      Comment


      • #4
        Re: Client computers cannot access Internet following ISP change

        Unfortunately I don't have any experience with ICS, I just know that the LAN NIC needs to route packets to the WAN NIC and that's likely where the problem is due to the ip address change on the WAN NIC. If there's an ICS management console I would just go in to it and start looking around. You could also look at the routing table on the server (run "route print" from a command prompt) to see if that gives you any clues. You may be able to delete any old static route that points to the old WAN NIC ip address and add a new route that points to the new ip address. You could also try rebooting the server to see if that clears up the problem.

        Comment


        • #5
          Re: Client computers cannot access Internet following ISP change

          Originally posted by joeqwerty View Post
          Unfortunately I don't have any experience with ICS, I just know that the LAN NIC needs to route packets to the WAN NIC and that's likely where the problem is due to the ip address change on the WAN NIC. If there's an ICS management console I would just go in to it and start looking around. You could also look at the routing table on the server (run "route print" from a command prompt) to see if that gives you any clues. You may be able to delete any old static route that points to the old WAN NIC ip address and add a new route that points to the new ip address. You could also try rebooting the server to see if that clears up the problem.

          Thanks Joe

          It seems that ICS is not a feature on SBS2003 not sure why

          Route print shows me


          Active Routes:
          Network Destination Netmask Gateway Interface Metric
          0.0.0.0 0.0.0.0 94.30.78.9 94.30.78.10 20
          91.85.230.224 255.255.255.248 91.85.230.227 94.30.78.10 20
          91.85.230.227 255.255.255.255 127.0.0.1 127.0.0.1 20
          91.255.255.255 255.255.255.255 94.30.78.10 94.30.78.10 20
          94.30.78.8 255.255.255.248 94.30.78.10 94.30.78.10 20
          94.30.78.10 255.255.255.255 127.0.0.1 127.0.0.1 20
          94.255.255.255 255.255.255.255 94.30.78.10 94.30.78.10 20
          127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1
          192.168.0.0 255.255.255.0 192.168.0.2 192.168.0.2 10
          192.168.0.2 255.255.255.255 127.0.0.1 127.0.0.1 10
          192.168.0.23 255.255.255.255 127.0.0.1 127.0.0.1 50
          192.168.0.255 255.255.255.255 192.168.0.2 192.168.0.2 10
          224.0.0.0 240.0.0.0 94.30.78.10 94.30.78.10 20
          224.0.0.0 240.0.0.0 192.168.0.2 192.168.0.2 10
          255.255.255.255 255.255.255.255 94.30.78.10 94.30.78.10 1
          255.255.255.255 255.255.255.255 192.168.0.2 192.168.0.2 1
          Default Gateway: 94.30.78.9
          ================================================== =========================

          Now 91.85.230.224 is an IP address associated with a back up connection that is not connected apparently ( I know its not connected wasnt aware that it had been configured) however this would have been there with the old connection active although was configured after the initial ISP connection that has just been replaced

          94.30.78.9 94.30.78.10 is the servers WAN IP addy is the gateway LAN IP on the router
          192.168,0,2 is the LAN IP on the server.

          Its all double dutch to me so please please help i am going crazy! Have spent all day on this!

          THx
          A

          Comment


          • #6
            Re: Client computers cannot access Internet following ISP change

            The routing table looks OK to me. You said this is SBS so how about running the CEICW again?

            Comment


            • #7
              Re: Client computers cannot access Internet following ISP change

              Originally posted by joeqwerty View Post
              The routing table looks OK to me. You said this is SBS so how about running the CEICW again?

              Hi Joe

              I did that 3 or 4 times today, followed by reboots and forced gpupdates for AD..

              Here is an IPConfig /all from the server, (I am remote desktopped on at the moment

              I am wondering if the 91.85.230.227 addres is an issue... and how to remove it if it is as it doesnt show on CEICW!

              C:\Documents and Settings\Administrator>ipconfig /all

              Windows IP Configuration

              Host Name . . . . . . . . . . . . : server
              Primary Dns Suffix . . . . . . . : hcmaint.local
              Node Type . . . . . . . . . . . . : Unknown
              IP Routing Enabled. . . . . . . . : Yes
              WINS Proxy Enabled. . . . . . . . : Yes
              DNS Suffix Search List. . . . . . : hcmaint.local

              PPP adapter RAS Server (Dial In) Interface:

              Connection-specific DNS Suffix . :
              Description . . . . . . . . . . . : WAN (PPP/SLIP) Interface
              Physical Address. . . . . . . . . : 00-53-45-00-00-00
              DHCP Enabled. . . . . . . . . . . : No
              IP Address. . . . . . . . . . . . : 192.168.0.23
              Subnet Mask . . . . . . . . . . . : 255.255.255.255
              Default Gateway . . . . . . . . . :
              NetBIOS over Tcpip. . . . . . . . : Disabled

              Ethernet adapter Server Local Area Connection:

              Connection-specific DNS Suffix . :
              Description . . . . . . . . . . . : HP NC105i PCIe Gigabit Server Adapter
              Physical Address. . . . . . . . . : 00-1E-0B-DC-08-2E
              DHCP Enabled. . . . . . . . . . . : No
              IP Address. . . . . . . . . . . . : 192.168.0.2
              Subnet Mask . . . . . . . . . . . : 255.255.255.0
              Default Gateway . . . . . . . . . :
              DNS Servers . . . . . . . . . . . : 192.168.0.2
              Primary WINS Server . . . . . . . : 192.168.0.2

              Ethernet adapter Wide Area Connection:

              Connection-specific DNS Suffix . :
              Description . . . . . . . . . . . : Realtek RTL8139 Family PCI Fast Ethernet
              NIC
              Physical Address. . . . . . . . . : 00-08-54-08-07-1F
              DHCP Enabled. . . . . . . . . . . : No
              IP Address. . . . . . . . . . . . : 91.85.230.227
              Subnet Mask . . . . . . . . . . . : 255.255.255.248
              IP Address. . . . . . . . . . . . : 94.30.78.10
              Subnet Mask . . . . . . . . . . . : 255.255.255.248
              Default Gateway . . . . . . . . . : 94.30.78.9
              DNS Servers . . . . . . . . . . . : 192.168.0.2
              NetBIOS over Tcpip. . . . . . . . : Disabled

              C:\Documents and Settings\Administrator>

              Comment


              • #8
                Re: Client computers cannot access Internet following ISP change

                Yeah, get rid of the 91.x.x.x ip address. It should be in the advanced properties of the WAN NIC. Also, if there's more than one gateway address lsited there get rid of it as well. It looks like there's an active PPTP connection to the server, is that correct? If so temporarily disable RRAS to see what happens. Run a tracert from a client to www.google.com to see where the tracert goes as this might give you an idea of where the problem is.

                Comment


                • #9
                  Re: Client computers cannot access Internet following ISP change

                  Originally posted by joeqwerty View Post
                  Yeah, get rid of the 91.x.x.x ip address. It should be in the advanced properties of the WAN NIC. Also, if there's more than one gateway address lsited there get rid of it as well. It looks like there's an active PPTP connection to the server, is that correct? If so temporarily disable RRAS to see what happens. Run a tracert from a client to www.google.com to see where the tracert goes as this might give you an idea of where the problem is.
                  The active PPTP is potentially my remote desktop connection or am i wrong?

                  I have taken the 91 address out and rerun CEICW for good measure

                  All I can now say is... where the hell do you live? I owe you several pints!

                  Comment


                  • #10
                    Re: Client computers cannot access Internet following ISP change

                    The PPTP connection (if I'm not mistaken) will only show in ipconfig/all if there's an active inbound PPTP connection. I don't know how SBS client connections work (whether they use PPTP, RDP, etc.) so that may be why there's an active PPTP connection. If the problem exists when no PPTP connection exists then it's probably not got anything to do with the problem. What does the tracert from a LAN client show?

                    Comment


                    • #11
                      Re: Client computers cannot access Internet following ISP change

                      Originally posted by joeqwerty View Post
                      The PPTP connection (if I'm not mistaken) will only show in ipconfig/all if there's an active inbound PPTP connection. I don't know how SBS client connections work (whether they use PPTP, RDP, etc.) so that may be why there's an active PPTP connection. If the problem exists when no PPTP connection exists then it's probably not got anything to do with the problem. What does the tracert from a LAN client show?
                      They use PPTP by default for RRAS/VPN. RDP connections wont show up there. They'll be logged under TSadmin.

                      Comment


                      • #12
                        Re: Client computers cannot access Internet following ISP change

                        I'm aware of that. Thanks. I manage a 50 server TS farm but have no knowledge of SBS. I saw he had an incoming PPTP connection active and was wondering how he was connected when he said he was connected remotely. I know that SBS uses some type of remote connections (RWW?) but didn't know if it used PPTP or RDP.

                        What type of remote connectivity does an SBS have set up "out of the box"?

                        Comment


                        • #13
                          Re: Client computers cannot access Internet following ISP change

                          Originally posted by joeqwerty View Post
                          I'm aware of that. Thanks. I manage a 50 server TS farm but have no knowledge of SBS. I saw he had an incoming PPTP connection active and was wondering how he was connected when he said he was connected remotely. I know that SBS uses some type of remote connections (RWW?) but didn't know if it used PPTP or RDP.

                          What type of remote connectivity does an SBS have set up "out of the box"?
                          As you said RWW and RRAS/VPN for clients. And of course the usual 2 administrative plus one console connection. RWW though leverages the RDP protocol indirectly and is proxyed on 4125. So you dont require 3389 open on the server inbound. Only 4125 inbound.

                          Comment


                          • #14
                            Re: Client computers cannot access Internet following ISP change

                            Thanks for the info.

                            Comment


                            • #15
                              Re: Client computers cannot access Internet following ISP change

                              Originally posted by scurlaruntings View Post
                              So you dont require 3389 open on the server inbound. Only 4125 inbound.
                              And 443, of course!
                              TIA

                              Steven Teiger [SBS-MVP(2003-2009)]
                              http://www.wintra.co.il/
                              sigpic
                              Iím honoured to have been selected for the SMB 150 list for 2013. This is the third time in succession (no logo available for 2011) that I have been honoured with this award.

                              We donít stop playing because we grow old, we grow old because we stop playing.

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