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Legacy Number Resource Information


Internet Protocol (IP) address space was originally administered by Jon Postel via a function known as the Internet Assigned Numbers Authority (IANA) (RFC 1060). Early on, IP number resources were allocated liberally to any organization that fulfilled the simple request requirements without formal legal agreement. As the Internet grew globally, the administrative mechanisms of IP number resource distribution could not continue to be managed efficiently by a single individual or organization. This led to distribution of the registration and management responsibilities and ultimately to the formation of the Regional Internet Registry (RIR) system (RFC 1366).

When ARIN (one of the five RIRs) was formed in December 1997, it was tasked with the administration and management of the entire database of IPv4 addresses and ASNs that were not administered by either of the two existing European (RIPE NCC) and Asia-Pacific (APNIC) regional registries. These previously-assigned resources are often referred to as legacy number resources. At its formation, the ARIN Board of Trustees decided that ARIN would provide registration services for these legacy number resources without requiring legacy resource holders to enter into a registration services agreement or pay service fees.

What Services are Provided to Legacy Number Resource Holders Not Under a Services Agreement with ARIN?
Service Provided by ARIN?
Maintain unique registration in ARIN's Whois Yes
Update and manage publicly available data in ARIN's Whois Yes
Manage reverse DNS delegations Yes
Online maintenance of registry records (ARIN Online) Yes
Resource Public Key Infrastructure (RPKI) access No
DNS Security (DNSSEC) access No

Early Registration Transfer Project

As the RIR system matured, it was decided that the interests of the legacy resource holders would be best served by having these resources administered by the RIR operating in the region where the resources were being used. The outcome of consultations with the community led to the development of the Early Registration Transfer (ERX) project, whereby early registrations were moved from the ARIN database into the appropriate RIR databases beginning in 2003. These number resources are now administered by the respective RIR in the region where the resources are being used.

Additional Information for Legacy Number Resource Holders

Number resources must be held by the organization to which they were originally assigned to be considered legacy number resources. When legacy number resources are transferred to another organization through a specified transfer (NRPM 8.3 and 8.4), the recipient organization is required to sign ARIN's Registration Services Agreement (RSA) and the resources being transferred will not retain their legacy status. In cases where number resources are transferred due to a company merger or acquisition (NRPM 8.2), the organization receiving the resources will have the option to retain legacy status in the signed RSA for any IPv4 resources that were originally registered prior to 22 December 1997.

If a legacy number resource holder requests new number resources directly from ARIN, they will be required to sign ARIN’s standard RSA which will cover only the resources being assigned by ARIN. Any legacy number resources that an organization currently holds will retain legacy status and will not be covered under the standard RSA unless that organization specifically requests it.

Any organization or individual in the ARIN service region who holds legacy Internet number resources not covered under any other RSA with ARIN has the option to sign ARIN's Legacy Registration Services Agreement (Legacy RSA or LRSA) at any time if they choose to do so.

If you have questions, please see the "Legacy RSA" section of the Registration Services Agreement FAQ.

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