IP Anycast

IP Anycast is  a type of routing where there is a one-to-many relationship between the servers and IPs.  In a normal network configuration there is only one server that will respond to a particular network IP address.  But in an IP anycast network there will be multiple computers / servers that will respond to a particular network IP address.  Based upon the network routing paths (AS paths in BGP) a computer requesting a server in an IP anycast configuration will connect so it’s closest system.  This makes IP Anycast necessary in an enterprise DNS configuration. 

All queries from the resolving name servers will go to the closest possible authoritative name server.