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  • naive networking question

    I'm running 2 win2k8 on Dell's Power edge servers
    1st server is dedicated to web based application it has 2 NICs
    Internal and external NIC adapters
    internal NIC is connected to Database Server SqlServer2008
    with following ip address 172.168.1.1
    NIC on database server has the following IP address 172.16.1.2
    with subnet 255.255.0.0
    external NIC has real static ip address which is accessible from any where on the planet
    Web server and database server are connected via UTP Cat6 cable

    i was doing normal ping check up to test connectivity between the servers
    i noticed the following
    the database whose ip is 172.16.1.2 was shutdown completely ( poweroff )
    but there was a host responding to my ping
    it seems to be VLAN interface or a switch and it seems to be remote
    please note that the internal NIC has no gateways entry just subnet mask and ip address on both servers ( db and web )

    the host seems to be remote or under heavy load due to deleayed response time

    Code:
    ping 172.16.1.2
    
    Pinging 172.16.1.2 with 32 bytes of data:
    Reply from 172.16.1.2: bytes=32 time=88ms TTL=57
    Reply from 172.16.1.2: bytes=32 time=85ms TTL=57
    Reply from 172.16.1.2: bytes=32 time=6ms TTL=57
    Reply from 172.16.1.2: bytes=32 time=90ms TTL=57
    
    Ping statistics for 172.16.1.2:
        Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
    Approximate round trip times in milli-seconds:
        Minimum = 6ms, Maximum = 90ms, Average = 67ms
    so i did tracert from the server to host
    Code:
    tracert -d 172.16.1.2
    
    Tracing route to 172.16.1.2 over a maximum of 30 hops
    
      1    <1 ms    <1 ms    <1 ms  10.10.10.10
      2    <1 ms    <1 ms    <1 ms  10.181.90.5
      3     5 ms     3 ms     4 ms  172.22.90.101
      4    90 ms    84 ms    93 ms  172.22.3.101
      5    36 ms    29 ms    27 ms  172.22.1.101
      6    90 ms     5 ms     8 ms  172.16.1.2
    the question now how can i direct my ping requests only to db server without going out through Lan

    any ideas would be a great assist
    Thanks in advance

  • #2
    Re: naive networking question

    gurus of networking any ideas
    i'm stuck with this issue

    Comment


    • #3
      Re: naive networking question

      Please post an IPCONFIG/ALL from both servers, also a diagram of your network (switches, routers as well as servers)
      Tom Jones
      MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
      PhD, MSc, FIAP, MIITT
      IT Trainer / Consultant
      Ossian Ltd
      Scotland

      ** Remember to give credit where credit is due and leave reputation points where appropriate **

      Comment


      • #4
        Re: naive networking question

        Originally posted by [email protected] View Post
        with following ip address 172.168.1.1
        NIC on database server has the following IP address 172.16.1.2
        Please make sure that's just a typo in your post.

        Comment


        • #5
          Re: naive networking question

          Originally posted by Garen View Post
          Please make sure that's just a typo in your post.
          yes indeed it's a typo
          correct ip =172.16.1.2
          i'll post a diagram asap
          Last edited by [email protected]; 30th June 2009, 17:34.

          Comment


          • #6
            Re: naive networking question

            here is the output of ipconfig/all on the server exposed to the internet which has real static ip address
            please note ipv6 is installed on nic but its void

            Code:
            Microsoft Windows [Version 6.0.6001]
            Copyright (c) 2006 Microsoft Corporation.  All rights reserved.
            
            C:\>ipconfig/ALL
            
            Windows IP Configuration
            
               Host Name . . . . . . . . . . . . : APPSRV
               Primary Dns Suffix  . . . . . . . :
               Node Type . . . . . . . . . . . . : Hybrid
               IP Routing Enabled. . . . . . . . : No
               WINS Proxy Enabled. . . . . . . . : No
               DNS Suffix Search List. . . . . . : 
            
            Ethernet adapter Internal:
            
               Connection-specific DNS Suffix  . :
               Description . . . . . . . . . . . : Broadcom BCM5708C NetXtreme II GigE (NDIS
             VBD Client) #2
               Physical Address. . . . . . . . . : 00-1E-xx-xx-xx-xx
               DHCP Enabled. . . . . . . . . . . : No
               Autoconfiguration Enabled . . . . : Yes
               Link-local IPv6 Address . . . . . : fe80::14d8:7ef5:d579:df5b%11(Preferred)
               IPv4 Address. . . . . . . . . . . : 172.16.1.1(Preferred)
               Subnet Mask . . . . . . . . . . . : 255.255.0.0
               Default Gateway . . . . . . . . . :
               DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                                   fec0:0:0:ffff::2%1
                                                   fec0:0:0:ffff::3%1
               NetBIOS over Tcpip. . . . . . . . : Enabled
            
            Ethernet adapter External:
            
               Connection-specific DNS Suffix  . : 
               Description . . . . . . . . . . . : Broadcom BCM5708C NetXtreme II GigE (NDIS
             VBD Client)
               Physical Address. . . . . . . . . : 00-1E-xx-xx-xx-xx
               DHCP Enabled. . . . . . . . . . . : No
               Autoconfiguration Enabled . . . . : Yes
               IPv4 Address. . . . . . . . . . . : 193.227.xxx.xxx(Preferred)
               Subnet Mask . . . . . . . . . . . : 255.255.255.224
               Default Gateway . . . . . . . . . : 193.230.xxx.xxx
               DNS Servers . . . . . . . . . . . : 193.230.xxx.xxx
               NetBIOS over Tcpip. . . . . . . . : Enabled
            
            Tunnel adapter Local Area Connection* 8:
            
               Media State . . . . . . . . . . . : Media disconnected
               Connection-specific DNS Suffix  . : 
               Description . . . . . . . . . . . : isatap
               Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
               DHCP Enabled. . . . . . . . . . . : No
               Autoconfiguration Enabled . . . . : Yes
            
            Tunnel adapter Local Area Connection* 9:
            
               Media State . . . . . . . . . . . : Media disconnected
               Connection-specific DNS Suffix  . :
               Description . . . . . . . . . . . : isatap.{E6D976AF-2BC2-41B5-951B-697C174E6
            149}
               Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
               DHCP Enabled. . . . . . . . . . . : No
               Autoconfiguration Enabled . . . . : Yes
            
            Tunnel adapter Local Area Connection* 11:
            
               Connection-specific DNS Suffix  . : 
               Description . . . . . . . . . . . : Microsoft 6to4 Adapter
               Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
               DHCP Enabled. . . . . . . . . . . : No
               Autoconfiguration Enabled . . . . : Yes
               IPv6 Address. . . . . . . . . . . : 2002:c1e3:1304::c1e3:1304(Preferred)
               Default Gateway . . . . . . . . . : 2002:c058:6301::c058:6301
               DNS Servers . . . . . . . . . . . : 193.230.xxx.xxx
               NetBIOS over Tcpip. . . . . . . . : Disabled
            
            C:\>
            here's the output of second server database server
            please note the other NIC is disabled
            both database server connected to application server through cat6 UTP cable directly ( 2nd NIC on db server to 2nd NIC on application server )

            Code:
            Microsoft Windows [Version 6.0.6001]
            Copyright (c) 2006 Microsoft Corporation.  All rights reserved.
            
            C:\>ipconfig/all
            
            Windows IP Configuration
            
               Host Name . . . . . . . . . . . . : DataBaseServer
               Primary Dns Suffix  . . . . . . . :
               Node Type . . . . . . . . . . . . : Hybrid
               IP Routing Enabled. . . . . . . . : No
               WINS Proxy Enabled. . . . . . . . : No
            
            Ethernet adapter Local Area Connection 2:
            
               Connection-specific DNS Suffix  . :
               Description . . . . . . . . . . . : Broadcom BCM5708C NetXtreme II GigE (NDIS
             VBD Client) #2
               Physical Address. . . . . . . . . : 00-1E-xx-xx-xx-xx
               Autoconfiguration Enabled . . . . : Yes
               Link-local IPv6 Address . . . . . : fe80::9dec:79a4:718f:b9ea%11(Preferred)
               IPv4 Address. . . . . . . . . . . : 172.16.1.2(Preferred)
               Subnet Mask . . . . . . . . . . . : 255.255.0.0
               Default Gateway . . . . . . . . . :
               DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                                   fec0:0:0:ffff::2%1
                                                   fec0:0:0:ffff::3%1
               NetBIOS over Tcpip. . . . . . . . : Enabled
            
            Tunnel adapter Local Area Connection* 9:
            
               Media State . . . . . . . . . . . : Media disconnected
               Connection-specific DNS Suffix  . :
               Description . . . . . . . . . . . : isatap.{785AF28F-EE3A-4558-9BCD-B0D7BFE05
            D5A}
               Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
               DHCP Enabled. . . . . . . . . . . : No
               Autoconfiguration Enabled . . . . : Yes
            
            C:\>

            Comment


            • #7
              Re: naive networking question

              What does ping -a 172.16.1.2 reveal?
              What does it reveal when the database is powered up?
              What is returned when you ping the Server name?
              What entries are in DNS?
              Is the DNS on a DC at this site?
              Any other DNS within the Domain?
              Have any HOSTS. files been manually modified?
              Do any of the dual homed Servers have the 172.16.1.2 IP added to more than the 1 NIC?
              1 1 was a racehorse.
              2 2 was 1 2.
              1 1 1 1 race 1 day,
              2 2 1 1 2

              Comment


              • #8
                Re: naive networking question

                A1
                this is the output when pingging database server from application server
                please note that database server is powered on

                Code:
                 
                C:\> ping -a 172.16.1.2
                Pinging DataBaseServer [172.16.1.2] with 32 bytes of data:
                Reply from 172.16.1.2: bytes=32 time<1ms TTL=128
                Reply from 172.16.1.2: bytes=32 time<1ms TTL=128
                Reply from 172.16.1.2: bytes=32 time<1ms TTL=128
                Reply from 172.16.1.2: bytes=32 time<1ms TTL=128
                Ping statistics for 172.16.1.2:
                    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
                Approximate round trip times in milli-seconds:
                    Minimum = 0ms, Maximum = 0ms, Average = 0ms
                this is the output when pingging database server from application server
                please note database server is powered off
                Code:
                 
                C:\>ping -a 172.16.1.2
                Pinging 172.16.1.2 with 32 bytes of data:
                Reply from 172.16.1.2: bytes=32 time=80ms TTL=57
                Reply from 172.16.1.2: bytes=32 time=14ms TTL=57
                Reply from 172.16.1.2: bytes=32 time=79ms TTL=57
                Reply from 172.16.1.2: bytes=32 time=29ms TTL=57

                A2
                both servers have no DNS records

                A3
                we have no DC just stand alone servers and hosts

                i haven't modfified hosts file
                what do mean by "Do any of the dual homed Servers have the 172.16.1.2 IP added to more than the 1 NIC? 30th June 2009 19:45"

                Comment


                • #9
                  Re: naive networking question

                  Do you use DHCP? If so look for the 172.16.1.2 address and see what device has it. Also run ping -a 172.16.1.2 to see if the device that responds is resolved to it's name to see what it is.

                  Comment


                  • #10
                    Re: naive networking question

                    Since its a direct connection between two hosts, if one host is offline is link is down. If you look at your Internal NIC while the SQL server is powered off does it say "Media disconnected?"

                    Not sure why your public router is forwarding private IPs but beyond that its normal behavior.

                    Comment


                    • #11
                      Re: naive networking question

                      Originally posted by [email protected]
                      what do mean by "Do any of the dual homed Servers have the 172.16.1.2 IP added to more than the 1 NIC
                      Dual homed is where you have 2 network adapters in the one server.
                      Each adapter can have more than 1 IP address assigned to it. It is possible to have the same IP, 172.16.1.2 assigned to more than 1 network adapter.

                      Looking at the response times of the ping -a I asked you to do, there is a signifigant discrepency between the one where SQL is powered on and the one where it is powered off. It seems as if there is a network adapter somewhere on your network that has 172.16.1.2 assigned to it. It also appears that it may not be in your immediate vicinity.
                      Do you have a VPN connection to a branch office where the culprit could be hiding?
                      1 1 was a racehorse.
                      2 2 was 1 2.
                      1 1 1 1 race 1 day,
                      2 2 1 1 2

                      Comment


                      • #12
                        Re: naive networking question

                        no each NIC on both server has only 1 different ip address assigned
                        and we have no vpn connections to remote sites
                        Last edited by [email protected]; 3rd July 2009, 23:41.

                        Comment


                        • #13
                          Re: naive networking question

                          we have no DHCP all ips ar assigned manually
                          if server it responds as follows
                          C:\> ping -a 172.16.1.2
                          Pinging DataBaseServer [172.16.1.2] with 32 bytes of data:
                          Reply from 172.16.1.2: bytes=32 time<1ms TTL=128
                          Reply from 172.16.1.2: bytes=32 time<1ms TTL=128
                          Reply from 172.16.1.2: bytes=32 time<1ms TTL=128
                          Reply from 172.16.1.2: bytes=32 time<1ms TTL=128
                          Ping statistics for 172.16.1.2:
                          Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
                          Approximate round trip times in milli-seconds:
                          Minimum = 0ms, Maximum = 0ms, Average = 0ms
                          if it's not up the reply as the following

                          C:\>ping -a 172.16.1.2
                          Pinging 172.16.1.2 with 32 bytes of data:
                          Reply from 172.16.1.2: bytes=32 time=80ms TTL=57
                          Reply from 172.16.1.2: bytes=32 time=14ms TTL=57
                          Reply from 172.16.1.2: bytes=32 time=79ms TTL=57
                          Reply from 172.16.1.2: bytes=32 time=29ms TTL=57

                          Comment


                          • #14
                            Re: naive networking question

                            You will need to check each machine manually to find the rogue IP (and this is why DHCP is oh so much more superior than static IPs). Strange that it is not showing up as a clash when you boot the SQL server.

                            The ping reply times made me think that you may have had a VPN or similar connection to another office as they are so much slower than when the SQL is running.

                            What else is running on your network? Any users bring in laptops or smartphones? Any wireless devices or routers you have forgotten about?

                            Anyone got any ideas?
                            1 1 was a racehorse.
                            2 2 was 1 2.
                            1 1 1 1 race 1 day,
                            2 2 1 1 2

                            Comment


                            • #15
                              Re: naive networking question

                              yes i agree with you DHCP is far superior than static IPs
                              yes we bring our laptops but i think its not laptops or usual (PCs - workstations -servers ) hosts
                              i think its an active component of network equipments ( switch - router ) or even a Vlan interface
                              i asked network admin multiple times about this host , but it seems he don't know what it is because a third party company built this network
                              what do you suggest me to do determine the host what is

                              and we have no wi-fi connection in our site
                              Originally posted by biggles77 View Post
                              You will need to check each machine manually to find the rogue IP (and this is why DHCP is oh so much more superior than static IPs). Strange that it is not showing up as a clash when you boot the SQL server.

                              The ping reply times made me think that you may have had a VPN or similar connection to another office as they are so much slower than when the SQL is running.

                              What else is running on your network? Any users bring in laptops or smartphones? Any wireless devices or routers you have forgotten about?

                              Anyone got any ideas?

                              Comment

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