Many networks, including residential and enterprise networks, use what are known as private IP addresses. These addresses are not globally unique; the same address may be in use in thousands of networks around the Internet. Although the Domain Name System (DNS), is mostly thought of as converting domain names to IP addresses, it also converts IP addresses to names. And software in networks using private IP addresses will—by default—still send DNS queries for information about these private addresses out onto the public Internet.

DNS servers outside of these networks cannot give useful answers to DNS queries about addresses inside a private network. These DNS servers have no way of knowing how those addresses are used. For this reason, DNS queries on the public Internet for private addresses, or other addresses which are not globally unique, are considered to be junk traffic. They consume Internet resources paid for by others, with no useful purpose.

Since these addresses only have a local significance, it is considered the responsibility of the network operator to ensure that any DNS queries sent from their network about these addresses do not leave their network. This is usually accomplished by having a local DNS server set to answer those queries in some way that is useful to the network. However, not all network operators do this, and so these queries still leak onto the public Internet where they must be dealt with. In order to reduce the load on the root DNS servers, an important resource to everyone who uses the Internet, the AS112 project was born to soak up these leaking queries.

The project is a loosely coordinated group of network operators around the world, who volunteer their own resources to accept and respond to these DNS queries, reducing the load on the root servers and other important infrastructure. Operators who wish to volunteer deploy systems using a standard configuration described in a set of Request for Comments documents (RFCs, linked above) published by the Internet Engineering Task Force (IETF). Operators who run AS112 systems are encouraged to publish public statistics on the volume and type of queries they receive, to list themselves on the Operator Listing and to participate in the AS112 Operators' mailing list.

Since 2009, DNS-OARC has acted as steward for the resources used by the project. OARC acts as the contact point for the address blocks and Autonomous System Number (AS 112), operates the DNS servers for the project's addresses and the as112.net domain name, and operates and maintains this web site and the above mailing list.

In 2023 this site was substantially redesigned and improved with the generous financial support of ARIN (the American Registry for Internet Numbers) via their Community Grant Program.