As indicated in the announcement issued today, ARIN’s IPv4 free pool has depleted. This is an important milestone for the Internet as we now usher in the age of IPv6.

As previously described in this blog series, ARIN has been placing /24s on hold for organizations over the past few months. This occurred when an organization qualified for a larger block size, but was given the option to accept our only available block size (/24) available at the time. They were given 30 days to decide if they would take the smaller block, or if they preferred to join the waiting list for unmet requests. In the case they chose not to accept the temporarily held /24, that block would go back into the inventory.

Even though we do not currently have an organization on the waiting list for unmet requests that will accept a block as small as a /24, we expect that to change after today’s depletion event. In the coming days we expect there will be organizations on the waiting list that will accept a /24.

Any /24s ARIN receives back into the inventory in the coming months as a result of an organization not accepting a temporarily held /24 would then be made available to organizations on the waiting list for unmet requests. Because of this activity, you will continue to see IPv4 address space issued to organizations by ARIN over the coming month even though we have reached depletion.

You will also see IPv4 address space issued to organizations on the waiting list over the next several months as ARIN receives small blocks of IPv4 address space resulting from a return or revocation of resources. We may also receive a distribution from the IANA twice a year in March or September, but a distribution is not guaranteed. ARIN’s most recent distribution from the IANA was received on 1 September 2015. This distribution included a /15 and two /16s that ARIN used to satisfy requests on the waiting list.

Aside from the expected IPv4 activity described above, ARIN will also continue issuing IPv4 addresses specifically reserved for the support of IPv6 transitions and Critical Internet Infrastructure, including Exchange Points. More information about those special use policies are described on the ARIN website. All other IPv4 registrations you see from ARIN will be the result of IPv4 transfers from this point forward. ARIN will continue satisfying IPv6 requests, as normal.

ARIN has reached depletion of the general IPv4 free pool today, 24 September 2015. We’ve been talking about the inevitability of IPv4 depletion for many years and have been educating the community about the need to get IPv6 resources and prepare public facing services for the IPv6 Internet, and now is the time to make sure you are taking steps toward preparing for IPv6 as soon as possible.