AS112

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The AS112 project is a group of volunteer-administered name server operators, who run an anycast instance of name servers that answer for the RFC 1918 reverse DNS networks, and the reverse address space of link-local RFC 3330 and RFC 3927 networks.

1. 10.0.0.0/8
2. 169.254.0.0/16
3. 172.16.0.0/12
4. 192.168.0.0/16

All of the AS112 nodes were originally run by a few of the Root nameserver operators, but later the group of volunteers has grown to include many other organizations.

Background

Before 2001, the in-addr.arpa zones for the RFC 1918 networks were delegated to a single instance of name servers, blackhole-1.iana.org and blackhole-2.iana.org, called the blackhole servers. The IANA-run servers were under increasing load from improperly-configured NAT networks, leaking out reverse DNS queries, which eventually caused unnecessary load on the root servers. The decision was made by a small subset of root server operators to run the reverse delegations using a model as described in RFC 3258; each announcing the network using the autonomous system number of 112.

Specific Configuration

The name servers participating in the AS112 project are each configured to answer authoritatively for the following zones:

• For the 10.0.0.0/8 network:
  • 10.in-addr.arpa
• For the 169.254.0.0/16 network (RFC 3927)
  • 254.169.in-addr.arpa
• For the 172.16.0.0/12 network:
  • 16.172.in-addr.arpa
  • 17.172.in-addr.arpa
  • 18.172.in-addr.arpa
  • 19.172.in-addr.arpa
  • 20.172.in-addr.arpa
  • 21.172.in-addr.arpa
  • 22.172.in-addr.arpa
  • 23.172.in-addr.arpa
  • 24.172.in-addr.arpa
  • 25.172.in-addr.arpa
  • 26.172.in-addr.arpa
  • 27.172.in-addr.arpa
  • 28.172.in-addr.arpa
  • 29.172.in-addr.arpa
  • 30.172.in-addr.arpa
  • 31.172.in-addr.arpa
• For the 192.168.0.0/16 network:
  • 168.192.in-addr.arpa
• For unique identification purposes:
  • hostname.as112.net

External sources

• AS112 web page
• RSSAC Meeting Atlanta 2002 Notes describing RFC 1918 network queries impact on the Root servers.
• Mailing list for AS112 operators.
• Building an AS112 node.
• Building an AS112 node using FreeBSD and OpenBGPD

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