Your Internet Consultant - The FAQs of Life Online

3.10. My system doesn't understand site names, but it does understand IP addresses. How do I get a site name resolved into an IP address?

Resolving a site name means finding out its corresponding IP address. Most systems, thanks to the domain name service, automatically translate a site name on the fly when you enter one (for instance, when you type telnet archie.au, the system knows you mean the computer at 139.130.4.6). You should never need to look up a name yourself, although you can if you really want.

There should be a name resolver on your system. On UNIX systems, look for a program called nslookup. Type nslookup followed by a site name and it will show you that site's IP address. Here's an example of an nslookup session: 

$ nslookup hal.gnu.ai.mit.edu
Server:  hustle.rahul.net
Address:  192.160.13.2

Name:    hal.gnu.ai.mit.edu
Address:  128.52.46.11
Some systems don't know how to translate site names to their corresponding IP addresses. In this case, you can use an e-mail resolving service. Send it a site name and you'll receive a message with the IP address for the site. Send an electronic mail message. 
To: resolve@cs.widener.edu
Subject: <subject line is ignored>
Body: site hal.gnu.ai.mit.edu
Another e-mail site resolver is available:
To: dns@grasp.insa-lyon.fr
Subject: <subject line is ignored>
Body: ip hal.gnu.ai.mit.edu

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