JPRS is operating a.dns.jp using IP Anycast technology, so the servers are distributed in geographically and network topologically. By this, high availability and tolerance to DoS attacks are ensured.
JPRS is operating a.dns.jp using independent AS number and Critical Infrastructure Address. As of Apr 2004, a.dns.jp servers are placed at Tokyo and Osaka, and connected to IXes and transit ISPs respectively.
A load balancing and routing technology that enables multiple hosts to provide a service or function to a single IP address normally assigned to one host on the Internet. Servers that use IP Anycast share a single IP address, and user requests are routed to the nearest server on the network.