Policy for Reverse Address Delegation of IPv4 and IPv6 Address Space in the RIPE 
NCC Service Region 

Olaf Kolkman
Leo Vegoda

Document ID: ripe-302
Date: 26 April 2004
Obsoletes: ripe-185, ripe-244

Abstract

This document describes the policy for reverse delegation of IPv4 and IPv6 address space 
in the RIPE NCC service region.

Contents

1.0 Introduction
2.0 Obtaining Delegation of an in-addr.arpa or ip6.arpa sub-domain
3.0 Procedures
4.0 References



1.0 Introduction

The RIPE NCC provides, as part of its services, the necessary support to enable the 
reverse resolution of IPv4 and IPv6 address space into domain names. This service is 
implemented under the in-addr.arpa and ip6.arpa sub-domains described in [1] and [2].

Reverse delegations for IPv4 and IPv6 addresses allocated by the RIPE NCC are made to 
Local Internet Registries (LIRs) and further delegated by the LIRs to Internet Service 
Providers or End Users. 

2.0 Obtaining Delegation of an in-addr.arpa or ip6.arpa sub-domain

The RIPE NCC provides reverse delegation for address space that has been allocated or 
assigned by the RIPE NCC. It also provides systems to control reverse delegations 
relating to early registrations that have been transferred to the RIPE Database. Registrants 
of address space allocations or assignments may delegate authority for requesting reverse 
delegation from the RIPE NCC.

The RIPE NCC accepts requests for reverse delegation for address space that has been 
allocated by the RIPE NCC to an LIR or, in the case of PI address space, an assignment 
that has been made to an End User.

3.0 Procedures

The procedures for requesting and modifying reverse delegation and information about 
the requirements the RIPE NCC enforces to maintain the quality of the reverse 
delegations are published at:

http://www.ripe.net/reverse/



4.0 References

[1] "Management Guidelines & Operational Requirements for the Address and Routing 
Parameter Area Domain ("arpa")"
[RFC 3172] 

[2] "DNS Extensions to Support IPv6 Address Aggregation and Renumbering" [RFC 
2874]