Working in the web hosting business, I need to often look up IP addresses and find out more about the servers that websites are hosted on every day. A Firefox add-on like ShowIP makes this job just a little ‘bit easier for me. With it installed, I can show the current IP address (or addresses) of the current page I am viewing in the Firefox status bar.
Once this add-on is installed, you will start to see IP addresses for the websites you view in the status bar of Firefox. When you right-click on the IP address shown, you will then have even more options to play with. You can copy the IP address to your clipboard, do a whois search on the IP in question, and much more.
It also has support for both IPv4 and IPv6. If the IP address is colored red, you know it is an IPv4 address and if it is green, then that tells you it is an IPv6 address. These colors can be customized, if red and green are not your favorite colors.
For webmasters or system administrators, this add-on is worth its weight in gold. You can pick up the ShowIP add-on for Firefox from the Firefox Add-ons website.