Internet Routing Registry

The Internet Routing Registry (IRR) is a set of public databases that allow Internet service providers (ISPs) to publish, and look up, the information they need to determine who is authorized to connect networks to the Internet. By validating this authorization, ISPs seek to prevent accidental or malicious route hijacking, which could cause Internet resources (such as websites and email) and people's Internet access to be interrupted or misdirected.

Source: Wikipedia — Internet Routing Registry (CC BY-SA 4.0)