Prefix WhoIs, the Widget?

The Prefix WhoIs widget displays the number of prefixes present within the global Internet routing table and allows the user to submit queries using a familiar Dashboard interface.
 
Prefix WhoIs displays the Origin-ASN and other interesting information related to the most specific prefix currently advertised within the Internet's global routing table that corresponds to the IP address in your query.

Mac OS X 10.4 Tiger is required. If you’re using Safari, click the download link. When the widget download is complete, show Dashboard, click the Plus sign to display the Widget Bar and click the widget’s icon in the Widget Bar to open it. If you’re using a browser other than Safari, click the download link. When the widget download is complete, unarchive it and place it in /Library/Widgets/ in your home folder. show Dashboard, click the Plus sign to display the Widget Bar and click the widget’s icon in the Widget Bar to open it.