Hack the Route Start free Open app IPv6
Anycast address
One address held by several devices; a packet to it reaches the nearest one.
IPv6 names three kinds of address: unicast (one card), multicast (every member of a group) and anycast (any one of several, the nearest by routing). Every router has the subnet-router anycast address of each prefix it forwards on, the prefix with an all-zeros interface id, so "a router on this link" is one address. On the internet, anycast is a routing trick: the same prefix announced from many places, as the DNS root servers do. Each router sends the address to its nearest holder, so failover is only as quick as the routing: a site that goes down must stop announcing it.