On Windows: start -> Run... -> cmd Enter "ipconfig" On Linux: Start a terminal session. Run "ifconfig" (usually in your /sbin or /usr/bin directory). If you have more than one Network adapter, these programs show you each adapter's IP address.
You can also try whatismyip.org for a cleaner display with no adds (and pretty much nothing else!). You are limited to three requests per minute.
Dude, you're right. I forgot even the case in point if your company is using a CACHE ENGINE or a PROXY to serve the pages into the network to you. In such case, the IP shown is the one your PC receives from the DHCP server or you have manually set, not the one the rest of the world sees from you. Good point. And BTW:
I tried setting up a section on my site to show your external IP plus your internal/proxy address ... for some reason the internal IP doesnt show up half of the time .. but you can try http://www.webzila.com/?wz=ipconfig