IPv4 Countdown Plan Update

Posted: Tuesday, 05 June 2012

On 23 April 2012 during ARIN XXIX in Vancouver, Leslie Nobile, Director of Registration Services gave a presentation on ARIN's plan to manage the distribution of its remaining IPv4 address pool.

You can view the presentation at:


We received some great input and in response have made a few adjustments to the Countdown Plan. 

  • The time window to complete payment and the RSA have been extended from 45 to 60 days.
  • Reinstatement of a 30 day hold period for returned, revoked and reclaimed resources during the final phase of the countdown, when ARIN supply is at or below one /8 equivalent.
  • The block size distribution of ARIN's remaining IPv4 inventory is now available on the page and will be updated daily.

The ARIN community has worked together over the last several years in developing policy to manage how ARIN allocates and assigns IPv4 addresses. ARIN has reviewed and refined its procedures to create an IPv4 Countdown Plan explaining how IPv4 requests will be processed as the remaining IPv4 address pool is distributed. We have posted the details of the plan at:

 The IPv4 Countdown is a dynamic process and we will notify the community as we approach and reach the trigger points for each new phase of the plan. ARIN will be updating and adding more information to the IPv4 Countdown page as we move through this process, so we strongly encourage you to pay attention to announcements and keep track of the current IPv4 inventory by monitoring the counter on the ARIN homepage. Because the IPv4 inventory may fluctuate on a daily basis, it is not intended as a tool to guide the timing of your IPv4 resource requests.


Communications and Member Services
American Registry for Internet Numbers (ARIN)