It's often useful to be able to find out what your external IP address is. I often check when I'm at client sites, to discover if I'm behind a NAT, remind myself whether I'm browsing through an SSH tunnel, and so on. There are a number of sites available that provide this service, e.g. whatismyip.com and myip.dk, but I recently decided to set one up on Kitserve. It's accessible at https://secure.kitserve.org.uk/ip/.
There are three reasons I chose to set it up rather than use the existing ones: the Kitserve server is on a secure connection, we don't have a usage restriction policy, and our page returns nothing but the IP address, i.e. no extraneous HTML, adverts, etc. This last point means that it can easily be called through scripts and the like, e.g. curl "https://secure.kitserve.org.uk/ip/". While whatismyip.com also offers a simplified version that returns only the IP address, it's not an easy url to remember.
If traffic starts getting too much then we may have to restrict usage, but for the time being the service will remain freely available to all. If you're intending to use it heavily we would appreciate being notified before you start, please see the Kitson Consulting contact page.