This is BwanaDik as originally brought to you by John Schilling (at http://www.jschilling.net/sw_bwanadik.php). This app tells you by way of a menubar icon whether or not you have an internet connection. It is green when all is good and red when you are not connected. Clicking on the icon will also give you your local and external IP addresses, as well as access to the app's settings for notifications and to the mac's network settings.
I have been using this app for years and find I can't live without it. I have revived it for Mavericks and thought it would be nice to see it on the app store so more people can enjoy this classic "killer app". This app will always remain free. I will do my best to keep it updated, and perhaps even add a thing or two if there is any demand for it.