Overview of TCP/IP Troubleshooting Tools

The following table lists the diagnostic utilities included with Microsoft TCP/IP that can be used to identify or resolve TCP/IP networking problems.

Table 12.1 TCP/IP Diagnostic Utilities

Utility

Used to

arp

View the ARP (address resolution protocol) table on the local computer to detect invalid entries.

hostname

Print the name of the current host.

ipconfig

Display current TCP/IP network configuration values, and update or release TCP/IP network configuration values.

nbtstat

Check the state of current NetBIOS over TCP/IP connections, update the LMHOSTS cache, and determine the registered name and scope ID.

netstat

Display protocol statistics and the state of current TCP/IP connections.

nslookup

Check records, domain host aliases, domain host services, and operating system information by querying Internet domain name servers.

ping

Verify whether TCP/IP is configured correctly and that a remote TCP/IP system is available.

route

Print the IP route table, and add or delete IP routes.

tracert

Check the route to a remote system.


For complete details about the TCP/IP utilities, see Appendix A, "TCP/IP Utilities Reference."

These additional Windows NT tools can be used for TCP/IP troubleshooting:

In general, when troubleshooting it is usually best to first verify that the computer TCP/IP configuration is correct, and then verify that a connection and route exist between the computer and network host by using ping, as described in the section "Test Connection to the TCP/IP Network by Using Ping" later in this chapter.

Compile a list of what works and what doesn't work, and then study the list to help isolate the failure. If link reliability is in question, try a large number of pings of various sizes at different times of the day, and plot the success rate. When all else fails, using a protocol analyzer, such as Microsoft Network Monitor, can be helpful.