prop-165: Provision of IPv4 Address Space to IPv6-only Networks for Transitional Purpose

This proposal aims to enable organizations eligible for IPv6 Provider Aggregatable (PA) address space to request and receive a limited IPv4 allocation, specifically a /24 block. This is intended to support the deployment of IPv6-only networks that still require minimal IPv4 resources for transitional purposes, such as DNS resolution.

Tomohiro Fujisaki and Hiroki Kawabata

1. APNIC’s Understanding of the Proposed Policy

APNIC understands this proposal as allowing members that hold an IPv6 allocation to request one IPv4 /24 delegation for IPv6-only network transition purposes.

The proposal is expected to affect a limited number of members. APNIC Secretariat notes that, as of 30 June 2026, 1.2% of APNIC members held IPv6 but not IPv4.

The proposal states that the IPv4 block must not be permanently reassigned to another organisation.

2. Impact of Proposed Policy on Registry and Addressing System

Registry systems would need to identify IPv4 /24 delegations made under this policy, link them to the member’s IPv6 allocation, and apply the specific policy conditions.

Additional clarification may be needed on whether these blocks can be temporarily reassigned or sub-assigned, given the proposal only prohibits permanent reassignment

The following question from the previous assessment still remain outstanding

• How should the Secretariat monitor if their IPv4 is being used to support their IPv6-only network and not being used for some other purpose?

3. Impact of Proposed Policy on APNIC Operation/Services

APNIC would need to create an assessment process for requests under this policy and provide guidance on how to conduct periodic reviews.

The Secretariat is requesting guidance on how they should periodically check whether the IPv4 resources remain necessary for transitional purposes.

The sunset provision requires further clarification before implementation. The proposal includes three separate triggers: projected exhaustion of the Final /8 pool within six months, a community-determined minimum threshold, and a determination by the APNIC Executive Council that continued operation would materially threaten equitable access to remaining IPv4 resources.

APNIC would need a clear operational method for applying these triggers, including how exhaustion projections are calculated, how often they are reviewed, what data is used, and how the result is published. The proposal does not currently define the community threshold, which would need to be specified before that trigger could be implemented.

The EC-based trigger would also require clarification, including the criteria for making such a determination, whether the suspension of new delegations is temporary or permanent, and how this interacts with the normal policy process.

4. Legal Impact of Policy

We note that the phrase ‘permanently re-assigned’ implies some form of reassignment may be allowed, provided it is not permanent. It would be helpful to understand if there is a deliberate intention behind this to guide our interpretation and the development of corresponding procedures.

The Proposed Policy will require a number of amendments to APNIC-127, however the specific implementation of such changes has not been made clear by the Authors. This uncertainty may create a number of enforcement and assessment challenges depending on its implementation, which can be considered further following clarification of the Secretariat’s questions in other parts of this impact assessment.

5. Implementation

Implementation would require clarification of the sunset mechanism, including the calculation method for projected exhaustion, the value and form of the community-determined threshold, and the process for any EC determination. APNIC would also need to define how applications in progress are handled if a sunset condition is triggered.
Until such point as these clarifications are made, we are unable to make a determination on implementation process and time frames.