Internet Security Router User
’s Manual
Appendix 15. Troubleshooting
141
Figure 15.1. Using the ping Utility
If the target computer cannot be located, you will receive the message
“Request timed out.”
Using the ping command, you can test whether the path to the Internet Security Router is working (using the
preconfigured default LAN IP address 192.168.1.1) or another address you assigned.
You can also test whether access to the Internet is working by typing an external address, such as that for
www.yahoo.com (216.115.108.243). If you do not know the IP address of a particular Internet location, you can
use the nslookup command, as explained in the following section.
From most other IP-enabled operating systems, you can execute the same command at a command prompt
or through a system administration utility.
15.1.2 nslookup
You can use the nslookup command to determine the IP address associated with an Internet site name. You
specify the common name, and the nslookup command looks up the name on your DNS server (usually
located with your ISP). If that name is not an entry in your ISP
’s DNS table, the request is then referred to
another higher-level server, and so on, until the entry is found. The server then returns the associated IP
address.
On Windows-based computers, you can execute the nslookup command from the Start menu. Click the Start
button, and then click Run. In the Open text box, type the following:
nslookup
Click
. A Command Prompt window displays with a bracket prompt (>). At the prompt, type the
name of the Internet address you are interested in, such as www.absnews.com.
The window will display the associate IP address, if known, as shown in Figure 15.2.