AS112 is a any-cast DNS service that helps mitigated the load on the global DNS system for DNS queries towards private IPv4 space, please check the AS112 project page for more details.

Many private and some public networks generate PTR (reverse lookup) queries for RFC 1918 addresses, dynamic DNS updates and other ambiguous addresses, such as the ones below:


The problem is the load this creates on the overall global DNS system: As more devices with private addresses connect to the Internet, the higher the load becomes without properly administered DNS servers for those devices.

In order to help the DNS system CNX is operating a AS112 note to capture those queries and answer them on behalf of the global DNS system. To redirect queries to the local AS112 service all PTR requests for private IP space is delegate to a set of well know any cast addresses. AS112 is announcing those address to the members at CNX.

Please ensure you accept AS112 announcements

Well Known Anycast Addresses used by AS112

The well known addresses for authoritative name service for zones associated with RFC1918 PTR queries are:

IPv4 Address IPv6 Address Function 2620:4f:8000::1 listed in SOA RR receives mostly updates 2620:4f:8000::6 listed in NS RR receives mostly queries 2620:4f:8000::42 listed in NS RR receives mostly queries

Note: is the stealth primary master for the zones

Well Known Anycast Addresses for DNAME

For the AS112 DNAME extensions, the following addresses are used:

IPv4 Address IPv6 Address 2001:4:112::/48