Part 4 -- Troubleshooting Tcp // IP: Structural Methods: Use

This updated guide examines Part 4 -- Troubleshooting Tcp // IP: Structural Methods: Use and organizes the essential facts, background, and practical takeaways in clear American English.

• The results of the Repair process cannot be saved for review or reporting purposes.

• On many computers, the Repair process must be performed separately from each network connection.

• The number of tests performed by the Repair process is limited.

These limitations can be overcome by using Netdiag.exe, a network connection troubleshooting tool in the Windows support tools component. Netdiag performs a series of more extensive tests and more tests than the Repair process does. You can also send Netdiag.exe output to a text file so you can record the tests performed and its results.

Install Netdiag

You can install Netdiag through the Windows Support Tools, which are installed by double-clicking SupportToolsSUPTOOLS. MSI . Default Support Tools installs to %% SystermDrive Program FilesSupport Tools but it is also easy to install on % SystemDrive% Tools because the tools need to run from the command line and this makes it easier to enter the public link This tool to run them. If you only want to install Netdiag and do not want other support tools, you can double-click the SupportToolsSupport.cab file and then double-click Netdiag.exe to install the tool.

Learn about Netdiag

Netdiag performs a series of tests on the internal system adapter. When these tests are done, Netdiag performs a series of global connection checks to identify and resolve connectivity issues that may be caused by problems outside the internal system.

Netdiag first performs the following check on the local system network adapters.

• Ndis • Ipconfig • Autonet • DefGw • NbtNm • WINS

When these tests are done Netdiag will perform a global connection check below:

• Member • NetBTTransports • Autonet • IpLoopBk • DefGw • NbtNm • Winsock • DNS • Browser • DsGetDc • DcKust • Trust • Kerberos • Ldap • Bindings • WAN • Modem • IPSec

Details of issues related to the above tests are provided in the table below:

Check NameDescription

AutonetCheck if APIPA is being used by the network adpapter.

BindingsList of network links including interface names, lowercase module names and uppercase letters indicating which links are currently enabled and reporting links.

BrowserLists all of the network protocols limited to the Browser and Redirector services.

CollectDcListlist of domain controllers.

DefGw

Verify connection with each default port configured

DNSVerify the suitability of the configured DNS server and verify the client's DNS registrations.

DsGetDcObtain the name of the domain controller from the directory service then obtain the name of the PDC Emulator.

Verify that the GUID domain name stored in Local Security Authority (LSA) is the same as the GUID domain name stored in DC. IpConfigList TCP / IP settings for each network adapter.

• IpLoopBkPing 127.0.0.1 revolving address for each adapter. IPSecCheck if IPsec is enabled and then list all active IPsec policies for the computer.
• IPXList statistics for IPX (if installed)KerberosVerify whether the Kerberos validation package is up to date.
• LdapContact all domain controllers and determine which LSAP authentication protocol is currently being used.
• MemberCheck to confirm the details of the primary domain, including computer role, domain name and domain GUID.
• Check if NetLogon service is started, add the primary domain name to the list of domains and query the main domain security identifier (SID).
• ModemProvides configuration information for each modem on the system.

Perform actions like the nbtstat -n command such as verifying the name of the Workstation Service workstation like the computer name and verifying that the Messenger = Service name and the Server Service name are displayed on all interfaces and not any of those names are in conflict.

• NdisList details related to the configuration of each network adapter including name, configuration, medium, GUID and statistics.
• NetBTTransportsList all the limited transmission protocols with NetBIOS over TCP / IP (NetBT).
• NetstatLists current TCP / IP connections and protocol statistics.
• NetwareQuery the nearest Netware server (if used) for the current login information.
• RouteList all static routes in the routing table and indicate whether they are persistent or not.
• TrustCheck domain trust relationships and verify that the primary domain SID is correct.
• WANSummary of settings and status for each COM port currently in use.
• WINSVerifies the compatibility of the configured WINS server and verifies WINS guest registrations.
• WinsockDisplays protocols and ports that match the WinSock service

In addition to performing the above tests, Netdiag.exe also reports information regarding the system as listed below:

• NetBIOS name of the system
• DNS name of the system
• General system information
• The installed hotfix

Run Netdiag

The simplest way to run Netdiag is to not need any parameters, which will check the local network adapter on the system and then perform a series of global connection tests. The output during the process of running this command on the Windows Server 2003 member server is given below (the hotfix book has been truncated):

C: toolsnetdiag ......

Computer Name: SRV DNS Host Name: SRV.contoso.com System info: Microsoft Windows Server 2003 R2 (Build 3790) Processor: x86 Family 15 Model 4 Stepping 1, GenuineIntel List of installed hotfixes: KB890046 KB893756 KB896358 . KB925486 Q147222

Netcard queries test.......: Passed

Per interface results:

Adapter: Local Area Connection

Netcard queries test...: Passed

Host Name.........: SRV IP Address........: 172.16.11.31 Subnet Mask........: 255.255.255.0 Default Gateway......: 172.16.11.1 DNS Servers........: 172.16.11.32

AutoConfiguration results......: Passed

Default gateway test...: Passed

NetBT name test......: Passed [WARNING] At least one of the 'WorkStation Service', 'Messenger Service', 'WINS' names is missing.

WINS service test.....: Skipped There is no WINS server configured for this interface.

Global results:

Domain membership test......: Passed

NetBT transports test.......: Passed The current NetBt configuration is defined: NetBT_Tcpip_{64B5D4FF-0014-4CC2-BB8D-9FB0C67CB75E} 1 The current NetBt is configured.

Autonet address test.......: Passed

IP loopback ping test.......: Passed

Default gateway test.......: Passed

NetBT name test..........: Passed [WARNING] You do not have an interface with only 'WorkStation Service', 'Messenger Service', 'WINS' names defined.

Winsock test...........: Passed

DNS test...: Passed

Redir and Browser test...: Passed List of current NetBt transactions connected to Redir NetBT_Tcpip_{64B5D4FF-0014-4CC2-BB8D-9FB0C67CB75E} The redir is bound to 1 NetBt transport.

List of current NetBt transactions connected to 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 Remote connection does not work.

Modem diagnostics test......: Passed

IP Security test.........: Skipped

Note: Run "netsh ipsec dynamic show /?" for more details

The command completed successfully

Note that running an NbtNm test will give you the following results:

NetBT name test......: Passed [WARNING] At least one of the 'WorkStation Service', 'Messenger Service', 'WINS' names is missing.

This warning is not really a problem because the Messenger service does not run on Windows Server 2003 by default, so no names are registered for it.

There are several ways you can run Netdiag like:

Netdiag / q performs checks in quiet mode and only reports errors.

• Netdiag / v performs checks in specific mode and provides additional details.
• Netdiag / test: test_name (s) performs standard checks and then they perform the specified tests.
• Netdiag / skip: test_name (s) performs a standard test against global checks except for the specified tests (Although some tests cannot be ignored like Member, Ndis and NetBTTransports)
• Netdiag / fix does all the global and standard checks, trying to fix any problems it finds.

For example, running the Netdiag / q test on the above system gives the following results:

C: tools  netdiag / q ......

Computer Name: SRV DNS Host Name: SRV.contoso.com System info: Microsoft Windows Server 2003 R2 (Build 3790) Processor: x86 Family 15 Model 4 Stepping 1, GenuineIntel List of installed hotfixes: KB890046 KB893756 KB896358 . KB925486 Q147222

Per interface results:

Adapter: Local Area Connection

Host Name.........: SRV IP Address........: 172.16.11.31 Subnet Mask........: 255.255.255.0 Default Gateway......: 172.16.11.1 Dns Servers........: 172.16.11.32

WINS service test.....: Skipped

Global results: [WARNING] You do not have an interface with only 'WorkStation Service', 'Messenger Service', 'WINS' names defined.

IP Security test.........: Skipped

The command completed successfully

Other examples of Netdiag

The best way to learn how to interpret Netdiag output is to try to run it under different test scenarios. Here are a few examples in different scenarios and output from this tool. These scenarios are performed by running Netdiag on the member server in a Windows Server 2003 domain, the output is truncated only highlighting the error messages reported by the tool.

1. Outputs when running netdiag / q with an offline domain controller :

Global results: [WARNING] You do not have an interface with just 'WorkStation Service', 'Messenger Service', 'WINS' names defined.

Redir and Browser test......: Failed [FATAL] Cannot send mailslot message to 'CONTOSO * MAILSLOTNETNETLOGON' via redir.[ERROR_BAD_NETPATH]

DC discovery test.........: Failed [FATAL] DC not found in domain 'CONTOSO'.[ERROR_NO_SUCH_DOMAIN]

DC list test............: Failed 'CONTOSO': Cannot find DC to get DC list from [try skipped].

Trust relationship test......: Failed [FATAL] Secure channel to domain 'CONTOSO' is broken.[RPC_S_SERVER_UNAVAILABLE]

Kerberos test............: Skipped 'CONTOSO': Cannot find DC to get DC list from [try skipped].

LDAP test.............: Failed No DC found to run LDAP tests on. The error encountered was: The specified name does not exist or cannot be associated.

[WARNING] DC not found in domain 'CONTOSO'.[ERROR_NO_SUCH_DOMAIN]

2. Output when running netdiag / q with the wrong default port configured on the system :

Default gateway test.......: Failed

[FATAL] NO GATEWAYS ARE REACHABLE.

You have not connected to other network segments.

If you configure IP mode, you need to add at least one valid gateway.

[WARNING] You do not have an interface with only 'WorkStation Service', 'Messenger Service', 'WINS' names defined.

DC list test...........: Failed DC connection error caused by using a browser. [ERROR_REQ_NOT_ACCEP]

3. Output when running netdiag / q with Computer Browser service not running on the system :

Global results: [WARNING] You do not have an interface with only 'WorkStation Service', 'Messenger Service', 'WINS' names defined.

DC list test...........: Failed DC connection error caused by using a browser.[NERR_ServiceNotInstalled]

4. Output when running netdiag / q with the computer account for the system disabled in Active Directory on startup

Global results: [WARNING] B?n không có m?t giao di?n ??n v?i vi?c 'WorkStation Servi ce ',' Messenger Service ',' WINS 'names defined.

Trust relationship test......: Failed Không th? th? thông báo channel cho mi?n 'CONTOSO' to DC 'DC-1A'. [ERROR_NO_LOG ON_SERVERS]

Kerberos test...........: Failed [FATAL] Không th? l?y khóa Cache t? Kerberos. L?i l?i ?ã là: (null)

Conclude

Netdiag.exe is a useful tool for troubleshooting network connectivity problems on Windows. We recommend readers of this article to try and find more scripts similar to some of the examples above to increase their understanding of the features of this tool and how to use it.

FAQ

What is Part 4 -- Troubleshooting Tcp // IP: Structural Methods: Use about?

It provides a structured overview of test, explains the main context, and highlights practical takeaways for readers.

Why does this topic matter?

Understanding the main concepts helps readers evaluate the issue, avoid common mistakes, and make better-informed decisions.

How should readers use this information?

Use the guidance as a practical starting point, confirm details that may have changed, and follow current product, safety, or security recommendations.