Identifying IP addresses is a common activity of network administrators, but when your environment contains a variety
of systems you might not know the commands for each system. This tip provides an overview of the different commands as well as some other ways to identify IP addresses on your network.
Numerous tools provide you information about your computer's IP addresses, as well as the IP addresses of computers and devices on your network. You can view you apparent IP address by going to www.whatismyip.com, www.whatismyipaddress.com, or to www.webyield.net/domainquery.html. If your connection is behind a proxy server you'll view your proxy server (or firewall's) assignment. To quickly find all of the IP addresses of your network adapters you can use the IPCONFIG /ALL command or on UNIX the IFCONFIG command. With both of these commands you can release and renew and perform other actions. You can find more information about options using the IPCONFIG /? Command or by checking your MAN files for UNIX. For earlier versions of Windows you'll want to use the WINIPCFG command.
The DOS NET command is another useful way of displaying network information. Use NET VIEW to list all the computers on your network. For Macintosh the command is NET ALL. To determine an IP address for any of the computers listed, use the PING <computername> command. The PING command will display the IP address of your target as well as testing for connectivity. The reverse command PING <ipaddress> returns the name of the computer associated with that address.
Asset management software will inventory your network IP addresses, as well as provide device discovery. These packages are often expensive and cumbersome, and meant to provide detailed topology information. If you want simpler information, IP addresses in a CSV format then check out Enterprise IP – Address Manager. A number of shareware tools exist to provide local IP addresses. Whatdayagot Pro 2003 audits your network to report on hardware and software, and will list IP addresses, as well as MAC addresses, and NIC data. The utility IP Finder reports your IP address, resolves DNS, and opens them in a browser. Both Whatdayagot Pro 2003 and IP Finder are available for download from www.download.com.
Barrie Sosinsky is president of consulting company Sosinsky and Associates (Medfield MA). He has written extensively on a variety of computer topics. His company specializes in custom software (database and Web related), training and technical documentation.