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  • Name resolution nightmare

    I've just this weekend had a massive clear out of the machine room, removed everything and plugged everything back in. Now everybody is complaining that access to servers is really slow (which it is).

    I have been pulling my hair out as all the servers show 1000Mbs (gigabit) connected speeds and I have no problems from my workstation, but most other people do.

    I've narrowed it down to a fault in name resolution. It seems that when I do from cmd
    Code:
    dir \\hostname\sharename
    it hangs for a very long time, but if I do
    Code:
    dir \\x.x.x.x\sharename
    I get an instant directory listing. Therefore WINS name resolution must be broken. But it works fine from my windows xp workstation, and from some others it hangs for ages...

    I don't understand, the wins server is running and answering requests, I have used nblookup to query my wins server directly, it returns the right ip instantly. I have unplugged and replugged the servers into different sockets to spread the switching load, giving more direct paths, I have flushed the dns and netbios caches, I have restarted my wins server and restarted a workstation to test this and it still doesn't work from those broken workstations. I JUST DON'T GET IT!

    Why can some workstations not resolve the name and others have no problem? One workstation which has this problem looks like a broadcast node accoring to ipconfig, the other is a hybrid so it should be using the wins server. In any case, I've also queried by broadcast the wins address and it's fast. I've also been testing my dns and it also gives an instant response.

    So why are these broken workstations failing to resolve the names of the servers properly? Are they broadcasting and not getting a reply, are they querying the wins server and not getting a reply or are they just themselves broken and if so how and why?

    I've seen something like this before but this is driving me nuts. When clearing the netbios cache the computer also hangs, so it looks like the problem is squarely the local netbios on the workstations.

    Any ideas or suicide pills welcome!

  • #2
    Re: Name resolution nightmare

    Doesn't look like WINS to me.

    What DNS server is your client using??

    What happens if you PING the server using its name??

    Is the firewall turned OFF on both the client and the server??

    Comment


    • #3
      Re: Name resolution nightmare

      it returns immediately. nslookup also works.

      the client has a firewall which will allow any response, the server has not firewall.

      Comment


      • #4
        Re: Name resolution nightmare

        You still haven't said what your clients DNS servers are.

        Comment


        • #5
          Re: Name resolution nightmare

          bind, but it doesn't matter, it works flawlessly, it's just dns services. No other connections are having problems that all use this dns service.

          Comment


          • #6
            Re: Name resolution nightmare

            Are all records correct registered in DNS??

            Do you have any rogue entries in your LMHOSTS or HOSTS file??

            Have you cleared the netbios cache??

            nbtstat -R

            Comment


            • #7
              Re: Name resolution nightmare

              Also what clients are havng issues??

              I'm presuming you have changed the NIC's as well??

              Comment


              • #8
                Re: Name resolution nightmare

                it's too many clients to be a NIC problem, several clients started having problems the day after the big rearranging of our server room, but they all worked fine before.

                Comment


                • #9
                  Re: Name resolution nightmare

                  From your first post

                  I get an instant directory listing. Therefore WINS name resolution must be broken. But it works fine from my windows xp workstation, and from some others it hangs for ages...
                  Are all your clients XP???

                  What are your servers?? Not actual hardware but OS.

                  Comment


                  • #10
                    Re: Name resolution nightmare

                    one 2000, the others are XP Sp2.

                    Comment


                    • #11
                      Re: Name resolution nightmare

                      And the servers??

                      Comment


                      • #12
                        Re: Name resolution nightmare

                        Check the crossover (or matrix) cables linking the switches.
                        1 1 was a racehorse.
                        2 2 was 1 2.
                        1 1 1 1 race 1 day,
                        2 2 1 1 2

                        Comment


                        • #13
                          Re: Name resolution nightmare

                          so far I have only been investigating this issue on workstations. I'm pretty sure they're cables connecting the switches are normal cat5e cables, not crossover cables.

                          Comment


                          • #14
                            Re: Name resolution nightmare

                            humbletech99,

                            Maybe you should start providing more info.
                            I still have not the magic to see what happens there.

                            What are the clients oses?
                            What are the Server OSes?
                            What are you're dns servers from you're clients and servers?
                            What is the DNS server (Os etc)
                            What is you're Gateway?
                            What happens if you run a tracert towards the server?
                            Did you already made a sniffertrace?
                            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


                            • #15
                              Re: Name resolution nightmare

                              Are your DNS Servers running on a *nix OS (assuming since running BIND)?

                              I have had BIND servers refuse connections before and cause this issue. Had to restart just the NAMED/BIND Process. I even have 1 DNS server that you have to restart just the process everytime the server is rebooted. NAMED has a problem and haven't found it yet. It affected certain clients too because of the way the clients recieved their DNS IP's.

                              To check the status try the below commands:
                              Red Hat Enterprise/CentOS/Fedora - service named status
                              Other Distros try - /etc/init.d/named status
                              Not 100% sure on the Other Distros because they are all built different

                              If either of the commands displays a refused connection message change status to restart and see what happens

                              Note - Can use start, stop, restart with named also
                              Hope this helps.

                              Nate

                              My advice is provided AS IS, without warranty of any kind, express or implied. Follow at your own risk.

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