How To Diagnose and Test TCP/IP or NetBIOS Network Connections in Windows Server 2003 (323388)


The information in this article applies to:

  • Microsoft Windows Server 2003, Datacenter Edition
  • Microsoft Windows Server 2003, Enterprise Edition
  • Microsoft Windows Server 2003, Standard Edition
  • Microsoft Windows Server 2003, Web Edition
  • Microsoft Windows Server 2003, 64-Bit Datacenter Edition
  • Microsoft Windows Server 2003, 64-Bit Enterprise Edition
  • Microsoft Windows Small Business Server 2003, Standard Edition
  • Microsoft Windows Small Business Server 2003, Premium Edition
This article was previously published under Q323388
For a Microsoft Windows 2000 version of this article, see 300986.

IN THIS TASK

SUMMARY

This article tells how to diagnose and test Transmission Control Protocol/Internet Protocol (TCP/IP) or NetBIOS network configurations. It also tells how to use of the most common diagnostic tools and provides basic network analysis techniques.

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Your Computer Configuration

If you want to troubleshoot a TCP/IP networking problem, first check the TCP/IP configuration of the computer that is experiencing the problem.

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To View the TCP/IP Configuration by Using the Ipconfig.exe Tool

  1. Click Start, click Run, type cmd in the Open box, and then press ENTER.
  2. At the command prompt, type ipconfig, and then press ENTER. This command returns your computer's DNS suffix, IP address, subnet mask, and default gateway.
  3. If you need more information and want to display a detailed configuration report, type ipconfig /all at the command prompt, and then press ENTER.
  4. Confirm that your computer has the appropriate settings for Domain Name System (DNS) and Windows Internet Name Service (WINS) servers, an available IP address, the correct subnet mask, the correct default gateway, and the correct host name.
NOTE: To see additional options of the Ipconfig.exe tool, type ipconfig /? at the command prompt.

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To Display Connection Information by Using the Nbtstat.exe Tool

NetBIOS over TCP/IP (NetBT) resolves NetBIOS names to IP addresses. TCP/IP provides many options for NetBIOS name resolution, including local cache lookup, WINS server query, broadcast, DNS server query, and LMHOSTS and HOSTS lookup.

Nbtstat.exe is a useful tool for troubleshooting NetBIOS name resolution problems. You can use the NBTSTAT command to remove or correct preloaded entries. To use the NBTSTAT command:
  • To list the NetBIOS table of the local computer, type nbtstat -n at the command prompt, and then press ENTER. This command returns the NetBIOS local name table. It indicates whether each name is a unique name or a group name and whether the name is registered or unregistered on the network.
  • To list the contents of the NetBIOS name cache, type nbtstat -c at the command prompt, and then press ENTER. This command shows the NetBIOS name cache, which contains name-to-address mappings for other computers.
  • To clear the contents of the name cache and reload it from the LMHOSTS file, type nbtstat -R at the command prompt, and then press ENTER.

    NOTE: Make sure that you use an uppercase "R".
  • To display the name table of a remote computer, type nbtstat -a RemoteComputerName at the command prompt, and then press ENTER, where RemoteComputerName is the NetBIOS computer name of the remote computer. The adapter status command returns the local NetBIOS name table for that computer and the MAC address of the network adapter.
  • To display a list of client and server connections, type nbtstat -s at the command prompt, and then press ENTER. This command lists the current NetBIOS sessions and their status, including statistics, as shown in the following example. 

   NetBIOS Connection Table 

   Local Name     State      In/Out  Remote Host   Input  Output 
   ------------------------------------------------------------------ 
   DAVEMAC1 <00>  Connected  Out     CNSSUP1<20>   6MB    5MB 
   DAVEMAC1 <00>  Connected  Out     CNSPRINT<20>  108KB  116KB 
   DAVEMAC1 <00>  Connected  Out     CNSSRC1<20>   299KB  19KB 
   DAVEMAC1 <00>  Connected  Out     STH2NT<20>    324KB  19KB 
   DAVEMAC1 <03>  Listening

NOTE: To see additional options of the Nbtstat.exe tool, type nbtstat /? at the command prompt.

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Testing Connections to Remote Servers

If you cannot connect to a remote server, there are two common tools that you can use. Use the PING command to verify that a host computer can connect to the TCP/IP network and network resources. Use the TRACERT command to examine the route taken to a destination.

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To Test Connections by Using PING

You can use the PING command as a troubleshooting tool to sequentially test connectivity to various network resources. To "ping" a network host directly:
  1. Click Start, click Run, type cmd in the Open box, and then press ENTER.
  2. Type one of the following lines, and then press ENTER, where IPAddressOfRemoteNetworkHost is the IP address of the computer that you want to connect to, and HostName is the name of the computer that you want to connect to:
    • ping IPAddressOfRemoteNetworkHost

      For example, ping 192.168.104.
    • ping HostName

      For example, ping www.microsoft.com.
  3. In the command prompt window, look for a reply that may look similar to the following:

    Reply from 192.168.1.104: bytes=32 time=40ms TTL=61
    Reply from 192.168.1.104: bytes=32 time=40ms TTL=61
    Reply from 192.168.1.104: bytes=32 time=40ms TTL=61
    Reply from 192.168.1.104: bytes=32 time=40ms TTL=61

    If you receive a similar response, the server is available on the network. If you cannot contact the resource, you can troubleshoot the connection by using the PING command to test connectivity to various network resources:
    1. Ping the loopback address to verify that TCP/IP is installed and working correctly on the local computer. To do so, type ping 127.0.0.1.
    2. Ping the IP address of the local computer to verify that it was added to the network correctly.
    3. Ping the IP address of the default gateway to verify that the gateway is functional and it is possible to connect to a local host on the local network. You can obtain the IP address of the local default gateway by using the IPCONFIG command.
    4. Ping the IP address of another remote host to verify that you can communicate through a router.
NOTE: To see additional options of the Ping.exe tool, type ping /? at the command prompt.

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To Test Connections by Using Tracert.exe

Tracert.exe is a route-tracing utility that you can use to determine the network path to a destination. The TRACERT command shows the series of IP routers that are used to deliver packets from your computer to the destination and shows how long it takes for each hop. If packets cannot reach the destination, the TRACERT command returns the name of the last router that successfully forwarded the packets. To determine the path that a packet takes on the network and where that path may be ending:
  1. Click Start, click Run, type cmd in the Open box, and then press ENTER.
  2. At the command prompt, type tracert IPAddressOfRemoteNetworkHost, and then press ENTER, where IPAddressOfRemoteNetworkHost is the IP address of the remote network host.
  3. Examine the results that appear in the window to determine the length of time that the packet took to reach each network segment and the point at which the connection may stop working.
NOTE: To see additional options of the Tracert.exe tool, type tracert /? at the command prompt.

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To Test Connections by Using the NET VIEW Command

  1. Click Start, click Run, type cmd in the Open box, and then press ENTER.
  2. At the command prompt, type net view \\ComputerName, and then press ENTER, where ComputerName is the name of the computer that you want to connect to.

    A list of the file and print shares on that computer is generated by establishing a temporary NetBIOS connection.
    • If there are no file or print shares available on the specified computer, you receive a "There are no entries in the list" message.
    • If the NET VIEW \\ComputerName command does not work and you receive a "System error has occurred" error message, follow these steps:
      1. Verify that you typed the correct name of the remote computer.
      2. Verify that the computer is operational.
      3. Verify that the computer is running the File and Printer Sharing for Microsoft Networks service.
      4. Use the PING command to verify that all the gateways (routers) between the local computer and the remote host are operational.
    • If the NET VIEW \\ComputerName command does not work, type net view \\IPAddressOfRemoteComputer, and then press ENTER.

      If the NET VIEW \\IPAddressOfRemoteComputer command works, but the NET VIEW \\ComputerName command does not work, the computer name may be resolving to the wrong address.
NOTE: To see additional options of the Net View tool, type net view /? at the command prompt.

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Troubleshooting

This section describes some of the issues that you may experience and tells how to troubleshoot them.

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I Can Contact a Network Resource Directly, but If I "Ping" the Resource, It Always Returns "Request Timed Out"

Many organizations block the return of ICMP (ping) packets as a security measure. As a result, if you try to ping a resource, you may not receive a response to the PING or TRACERT message.

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I Can Ping a Resource by Its IP Address, but I Cannot "Ping" It by Name

If you can contact a resource by using its IP address but a PING message to its host name does not work, the problem may be caused by a name resolution failure, instead of by network connectivity. Make sure that the computer is configured with the correct DNS or WINS entries, and that the DNS or WINS servers are available.

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Modification Type:MajorLast Reviewed:2/21/2006
Keywords:kbHOWTOmaster kbnetwork kbtool kbtshoot KB323388 kbAudITPro
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