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nslookup server unknown - can ping server name and IP

    Question

  • My customer has a tiny domain with one SBS2003R2 server, a few PCs and printers. The system is highly under used. The system has been in place and working fine for a long time but suddenly stopped sharing folders on the server.

    I found the server without an IP address, when I first arrived. The NIC is dual, so I moved the one cable to the other port and set the same static IP to get things going again. Then I discovered that DHCP from the only server had stopped. I enabled it in the firewall.

    The server and all the clients can get to the internet. They can ping the server by name and IP. Two weeks later no one can access the two network printers. DHCP suddenly begins working again, without any changes on my end other than stopping the firewall as DHCP.

    I am not well versed in the DNS and DHCP configuration utilites. I compared the settings to the SBS2007R2 server at work and things look normal.

    I found some troubleshooting tips and ran nslookup from the server and PCs. This utility reports that the domain is unknown but knows the server IP.

    From a PC I attempted to re-add one of the network printers. The add printer wizard found one of them and added it in a "Ready" state. Looking at the port configuration of the "new" printer, the IP address is correct. A test print fails, nor can I log into the printer's web port using http://192.168.1.210 - YET I can ping the same IP.

    I can log into the server from the internet to check email using OWA. I added new shared folders on the server but can not access them. Using Explorer and looking at my network places, I see the domain name but get errors when expanding the domain name to see the membership.

    My customer is willing to bring in a consultant at this point, as I am not a specialist.

     


    Deep Creek Services
    Thursday, July 08, 2010 9:59 PM

Answers

  • Ace,

    Thanks for your time and advice.

    I can't believe I never noticed the check marks in the Local Area Connections Properties interface. File and Printer sharing on the server was installed but unchecked. When I moved the LAN connection from the bad port to the good one I must have accidently unchecked it.

    File sharing is now restored. The network printers are not yet working but I lack admin access and their tech support was not able to help over the phone to save them a trip out to the site. I'm on to the next issues with this customer, who has a long list of broken systems.

    This server complains daily of maximum RAM (4 Gig on 32 bit OS) usage. I'll post in the relevant forum as I collect the facts. Mitel's Call Center config is the likely offender.


    Deep Creek Services
    • Marked as answer by Tiger Li Wednesday, July 14, 2010 6:53 AM
    Tuesday, July 13, 2010 12:10 PM

All replies

  • My customer has a tiny domain with one SBS2003R2 server, a few PCs and printers. The system is highly under used. The system has been in place and working fine for a long time but suddenly stopped sharing folders on the server.

    I found the server without an IP address, when I first arrived. The NIC is dual, so I moved the one cable to the other port and set the same static IP to get things going again. Then I discovered that DHCP from the only server had stopped. I enabled it in the firewall.

    The server and all the clients can get to the internet. They can ping the server by name and IP. Two weeks later no one can access the two network printers. DHCP suddenly begins working again, without any changes on my end other than stopping the firewall as DHCP.

    I am not well versed in the DNS and DHCP configuration utilites. I compared the settings to the SBS2007R2 server at work and things look normal.

    I found some troubleshooting tips and ran nslookup from the server and PCs. This utility reports that the domain is unknown but knows the server IP.

    From a PC I attempted to re-add one of the network printers. The add printer wizard found one of them and added it in a "Ready" state. Looking at the port configuration of the "new" printer, the IP address is correct. A test print fails, nor can I log into the printer's web port using http://192.168.1.210 - YET I can ping the same IP.

    My customer is willing to bring in a consultant at this point, as I am not a specialist.

     


    Deep Creek Services


    Hello Deep Creek Services,

    Actually this is an SBS question, and there's a separate forum for that, however, looking at your errors, it's definitely a network services configuration issue, such as probably solely based on DNS misconfig.

    First, when you invoke nslookup, it looks at the first DNS entry in the DNS list of the NIC that is on the top of the binding order (Network Connections, Advanced Menu, Advanced option), then it looks in DNS's Reverse Lookup Zone for a reverse zone for the IP subnet. If a PTR exists, it will tell you what the server name is, and if one doesn't, it simply says "Unknown." So this is not an error, just a message saying you don't have a reverse zone, or if you do, a PTR for the server does not exist.

    As far as the other stuff going on, to better assist in diagnosing this, and to save you a couple of bucks getting outside help, at least for starters, please post the following info:

    • An ipconfig /all from the server
    • An ipconfig /all from a sample DHCP enabled workstation
    • Any event log errors in any of the logs on the server (please post the EventID# and Source Name) 
    • Any event log errors in any of the logs on any of the workstations or laptops (please post the EventID# and Source Name)
    • Network layout, such as if there is a router/firewall, is that connected to the internet and the server, then the server is connected to the internal network, etc.
    • Is RRAS (VPN, etc) installed and configured on the server?

    The requested info should help us diagnose this for you.

    What I can say is this sure sounds like an external or non-AD DNS server is being used. We need to always make sure that no ISP or any other DNS addresses exist (such as the router/firewall as a DNS address, or your ISP's DNS servers used as a DNS address) on any of the NICs on the server or the client machines, or numerous issues can result. If DHCP is providing the client machines with such an address, please check DHCP Option 006 on the server to insure only the SBS' IP address is set, and remove any others. Also, don't use the router/firewall as a DHCP server, since it doesn't support or interact very well with Microsoft's DNS Dynamic Updates capabilities.

    Also, make sure that the DHCP Client service is set to Automatic and Started.

    In addition, you stated you compared settings against your other "SBS2007R2" server. I believe that is a typo because there's no such version. You may have possibly meant SBS 2003 R2?

    Ace


    Ace Fekay, MVP, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA 2003/2000, MCSA Messaging 2003, Microsoft Certified Trainer, Microsoft MVP - Directory Services. This posting is provided AS-IS with no warranties or guarantees and confers no rights.
    • Proposed as answer by Tiger Li Monday, July 12, 2010 3:16 AM
    Thursday, July 08, 2010 10:20 PM
  • The server at work is SBS2008 with SP2, aka Windows Server Standard FE 2007 SP2.

    What is PTR?

    The systems begins with a DSL modem to router/firewall appliance to managed switch to server. I'll have to collect the requested data.

    I'm confused about the misconfiged DNS possibility. The system worked for at least one year. No one made changes to my knowledge. However, a few ex-employees knew the passwords. They have now been changed. It seems unlikely that DNS config changes happened spontaneously.

    All support is appreciated. I'll return with the requested data, ASAP.

    Kurt 

     


    Deep Creek Services
    Friday, July 09, 2010 12:27 PM
  • The server at work is SBS2008 with SP2, aka Windows Server Standard FE 2007 SP2.

    What is PTR?

    The systems begins with a DSL modem to router/firewall appliance to managed switch to server. I'll have to collect the requested data.

    I'm confused about the misconfiged DNS possibility. The system worked for at least one year. No one made changes to my knowledge. However, a few ex-employees knew the passwords. They have now been changed. It seems unlikely that DNS config changes happened spontaneously.

    All support is appreciated. I'll return with the requested data, ASAP.

    Kurt 

     


    Deep Creek Services


    Kurt,

    Regarding the "FE" edition, you mean "Windows Server 2008 for Windows Essential Server Solutions" or "WinWESS". That was also known as Windows Server 2008 Standard FE. It was available outside the product suite, and it ONLY supports a maximum of 15 Client Access Licenses. I didn't realize many run this version.

    A PTR is a "Pointer" record, or a reverse record in a reverse lookup zone. An example of a Forward Lookup Zone is your zone name in DNS, such as mydomain.com or mydomain.local, etc. That would contain "A" or Host records such as for your domain controller (the SBS), your workstations, etc, and their associated IP addresses. An example of a Reverse Lookup Zone is 192.168.10.x. This contains Pointer records, such as IP addresses, that point to their cooresponding Host FQDNs.

    How to create a reverse lookup zone:
    http://www.youtube.com/watch?v=wRQTFiGznfA&feature=related

    Adding a Reverse Lookup Zone (A more indepth explanation)
    http://technet.microsoft.com/en-us/library/cc961414.aspx

    DNS can be misconfigured and work for a long time. I've seen installations using their router/firewall as a DNS address and got away with it for quite a long time until one day a client is getting denied to use a printer. I'm not saying this is true in your case or not, just stating it's a possibility.

    Looking forward to the data. Thanks!

    Ace

     

     


    Ace Fekay, MVP, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA 2003/2000, MCSA Messaging 2003, Microsoft Certified Trainer, Microsoft MVP - Directory Services. This posting is provided AS-IS with no warranties or guarantees and confers no rights.
    • Proposed as answer by Tiger Li Monday, July 12, 2010 3:16 AM
    Friday, July 09, 2010 2:27 PM
  • Ace,

    Thanks for your time and advice.

    I can't believe I never noticed the check marks in the Local Area Connections Properties interface. File and Printer sharing on the server was installed but unchecked. When I moved the LAN connection from the bad port to the good one I must have accidently unchecked it.

    File sharing is now restored. The network printers are not yet working but I lack admin access and their tech support was not able to help over the phone to save them a trip out to the site. I'm on to the next issues with this customer, who has a long list of broken systems.

    This server complains daily of maximum RAM (4 Gig on 32 bit OS) usage. I'll post in the relevant forum as I collect the facts. Mitel's Call Center config is the likely offender.


    Deep Creek Services
    • Marked as answer by Tiger Li Wednesday, July 14, 2010 6:53 AM
    Tuesday, July 13, 2010 12:10 PM
  • Ace,

    Thanks for your time and advice.

    I can't believe I never noticed the check marks in the Local Area Connections Properties interface. File and Printer sharing on the server was installed but unchecked. When I moved the LAN connection from the bad port to the good one I must have accidently unchecked it.

    File sharing is now restored. The network printers are not yet working but I lack admin access and their tech support was not able to help over the phone to save them a trip out to the site. I'm on to the next issues with this customer, who has a long list of broken systems.

    This server complains daily of maximum RAM (4 Gig on 32 bit OS) usage. I'll post in the relevant forum as I collect the facts. Mitel's Call Center config is the likely offender.


    Deep Creek Services


    I'm glad to have helped out pointing out where the settings are. As for the printers, yes, you would need administrative rights to administer them or troubleshoot them.

    I'm not familiar with Mitel's software, so I can't help with it. If you find it's something else, such as DNS, which is known to eat up RAM, but not multiple GIGs of it, let us know.

    Ace


    Ace Fekay, MVP, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA 2003/2000, MCSA Messaging 2003, Microsoft Certified Trainer, Microsoft MVP - Directory Services. This posting is provided AS-IS with no warranties or guarantees and confers no rights.
    Tuesday, July 13, 2010 11:41 PM