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.

[edit] 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. 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.

[edit] 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

[edit] 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.