I discovered a FireFox add-on this morning called ShowIP. As the name suggests, it shows the IP of the current website you are connected to in the lower right corner of the status bar. It really helped me today because I had to allow a HTTPS site in our internet filtering software and the only way it works with HTTPS is to add it by IP (https://xxx.xxx.xxx.xxx:443).
The site I was trying to get the IP for would not seem to let my get it with common tools like whois or nslookup. Also, our internet logging software is not currently logging correctly, so I couldn’t get it that way. This little plugin got the address right away and I was able to add what I needed so that the users can access the site.
I’d also like to add that a couple other addons for FF that I absolutely love are Noscript (duh), and Context Search. So check those out if you haven’t. I can’t surf without those now. Hell, I find myself trying to use context search in other programs like Outlook, then going… oh yeah – can’t.