Appendix B: Ping and TCP/IP Debugging Tools
Because TCP/IP is so common, Windows® and many UNIX® systems have
These debugging programs are executed at the command line prompt of the operating system (see the end of this section for more information about the command line).
ping
The most popular TCP/IP debugging program is called “ping” (after the name given to the operation of submarine sonar devices). Like the sonar, ping sends out a packet to an address that you specify and waits for a reply. Although very simple to use, ping is extremely powerful because it works at the IP level and often will respond even when the higher level TCP layer cannot. As mentioned above, pinging capability is included with most systems and there are also many shareware implementations.
USE: Determine if a workstation is connected to the network. Routers, servers, and workstations are identified by an IP address and possibly a “name.” The IP address is a numeric string whose format is referred to as “dotted decimal” (example: 192.168.0.0.). The “name” can be any name given to a computer when it is installed or an internet URL. The ability to use a name is provided by a server’s DNS (Domain Name Service). The DNS has a lookup table that cross references IP addresses to names. If a DNS service is not available, you will need to use the IP address.
EXAMPLE OF USE:
#1: You have problems connecting to the Black Box Web site from a workstation, and you know the DNS name of the website is “www.blackbox.com”. At the workstation’s Command Prompt, enter “ping www.blackbox.com.” If connected, you will receive back blackbox.com's IP address (for example, 207.115.64.64) and the roundtrip time of your ping packet.
Page 71 |
