Learn how to use the Netdiag.exe support tool to diagnose TCP/IP connectivity issues in this tip from WindowsNetworking.com.
In the last article of this series we examined how to repair network connections using the "Repair" feature of Windows network connections. The Repair feature works by performing a series of tests to try and restore network connectivity caused by network misconfiguration on either the client (issues with DHCP settings or resolver cache) or server (name registration with WINS or DNS server). The Repair feature has several limitations however, namely:
These limitations can be overcome by using Netdiag.exe, a network connectivity troubleshooting tool that is part of the Windows Support Tools. Netdiag runs a more extensive series of tests than the Repair process does, and it performs many more tests than the Repair process does. You can also redirect output for Netdiag.exe to a text file so you can have a record of the tests performed and their results.
Installing Netdiag
You can install Netdiag by installing the Windows Support Tools, which can be installed by double-clicking on \Support\Tools\SUPTOOLS.MSI. By default the Support Tools install to %SystermDrive%\Program Files\Support Tools but I find it easier to install them to %SystemDrive%\Tools since the tools need to be run from the command-line and this makes typing the path to these tools simpler to run them. Alternatively, if you only want to install Netdiag and not the other Support Tools, you can double-click on the \Support\Tools\Support.cab cabinet file and then double-click on Netdiag.exe to install this tool alone.
Understanding Netdiag
Netdiag performs a series of tests on each network adapter on the local system. Once these tests are performed, Netdiag performs a series of global connectivity tests to identify and resolve connectivity problems that may be caused by issues beyond the local
To continue reading for free, register below or login
To read more you must become a member of SearchNetworking.com
system.
Netdiag first performs the following tests on the local system's network adapters:
Once these tests are performed, Netdiag then performs the following series of global connectivity tests:
Details concerning each of these tests are provided by the following table:
[TABLE]
In addition to performing these tests, Netdiag.exe also reports the following information concerning the system:
Running Netdiag
The simplest way to run Netdiag is without any parameters, which tests each local network adapter on the system and then performs a series of global connectivity tests. Sample output from running this command on a Windows Server 2003 member server is as follows (hotfix list has been truncated):
C:\tools\netdiag
...................................
Netcard queries test . . . . . . . : Passed
Per interface results:
Global results:
Domain membership test . . . . . . : Passed
NetBT transports test. . . . . . . : Passed
List of NetBt transports currently configured:
NetBT_Tcpip_{64B5D4FF-0014-4CC2-BB8D-9FB0C67CB75E}
1 NetBt transport currently configured.
Autonet address test . . . . . . . : Passed
IP loopback ping test. . . . . . . : Passed
Default gateway test . . . . . . . : Passed
NetBT name test. . . . . . . . . . : Passed
[WARNING] You don't have a single interface with the <00> 'WorkStation Service', <03> 'Messenger Service', <20> 'WINS' names defined.
Winsock test . . . . . . . . . . . : Passed
DNS test . . . . . . . . . . . . . : Passed
Redir and Browser test . . . . . . : Passed
List of NetBt transports currently bound to the Redir
NetBT_Tcpip_{64B5D4FF-0014-4CC2-BB8D-9FB0C67CB75E}
The redir is bound to 1 NetBt transport.
List of NetBt transports currently bound to the browser
NetBT_Tcpip_{64B5D4FF-0014-4CC2-BB8D-9FB0C67CB75E}
The browser is bound to 1 NetBt transport.
DC discovery test. . . . . . . . . : Passed
DC list test . . . . . . . . . . . : Passed
Trust relationship test. . . . . . : Passed
Secure channel for domain 'CONTOSO' is to '\\DC-1A.contoso.com'.
Kerberos test. . . . . . . . . . . : Passed
LDAP test. . . . . . . . . . . . . : Passed
Bindings test. . . . . . . . . . . : Passed
WAN configuration test . . . . . . : Skipped
No active remote access connections.
Modem diagnostics test . . . . . . : Passed
IP Security test . . . . . . . . . : Skipped
Note: run "netsh ipsec dynamic show /?" for more detailed information
The command completed successfully
Note that running the NbtNm test gave the following results:
This warning is not really a problem since by default the Messenger service is not running on Windows Server 2003 so no <20> name will be registered for it.
There are other ways you can run Netdiag, specifically:
For example, running the Netdiag /q test on the above system produces these results:
C:\tools\netdiag /q
...................................
Per interface results:
Global results:
[WARNING] You don't have a single interface with the <00> 'WorkStation Service', <03> 'Messenger Service', <20> 'WINS' names defined.
IP Security test . . . . . . . . . : Skipped
The command completed successfully
More Netdiag examples
The best way of learning how to interpret Netdiag output is to try running it under various test scenarios. The following are a few examples of different scenarios and the kind of output you may get from this tool. These scenarios are performed by running Netdiag on a member server in a Windows Server 2003 domain, and the output has been truncated to highlight only the error messages reported by the tool.
Conclusion
Netdiag.exe is a powerful tool for troubleshooting network connectivity issues on Windows networks. Readers of this article are encouraged to try and think up additional scenarios similar to the examples above to help them gain more experience in understanding the capabilities of this tool and how to use it.
About the author:
Mitch Tulloch is a writer, trainer and consultant specializing in Windows server operating systems, IIS administration, network troubleshooting, and security. He is the author of 15 books including the Microsoft Encyclopedia of Networking (Microsoft Press), the Microsoft Encyclopedia of Security (Microsoft Press), Windows Server Hacks (O'Reilly), Windows Server 2003 in a Nutshell (O'Reilly), Windows 2000 Administration in a Nutshell (O'Reilly), and IIS 6 Administration (Osborne/McGraw-Hill). Mitch is based in Winnipeg, Canada, and you can find more information about his books at his Web site: www.mtit.com.
[TABLE]WindowsNetworking.com contains a wealth of networking information for administrators: Featuring information on how to setup and troubleshoot various networks of any size. Also includes a comprehensive archive of hundreds of reviewed networking software and hardware solutions. Frequently updated with articles and tips by a team of leading authors, it remains a favorite within the networking community.
