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.