CIDRv6.xyzAn interactive IPv6 address and CIDR range visualizer

CIDR is a notation for describing blocks of IP addresses and is used heavily in various networking configurations. IPv6 addresses contain 8 groups of 16 bits each (sometimes called hextets or quibbles) giving values between 0 and 65535 . The decimal value that comes after the slash is the number of bits consisting of the routing prefix. This in turn can be translated into a netmask, and also designates how many available addresses are in the block.