4or6 1.0.1

4or6 is a Firefox addon designed to identify if you are connecting to a website using the legacy Internet Protocol (IPv4) or the next generation Internet Protocol (IPv6). It does this by checking the local system IP addresses and the website IP addresses (via DNS), and then display an IPv4/IPv6 capability icon. 4or6 displays the icon as a button in the navigation toolbar (default), in the address bar next to the star icon or both.