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IPv4 IANA Free Pool Depletion – FAQ

Can I still get IPv4 address space from ARIN?

Yes, ARIN still has available IPv4 address space. We have developed an information sheet that explains the steps leading up to full depletion of the IPv4 address space. We cannot predict how long ARIN’s pool of IPv4 address space will last, but we will continue to distribute IPv4 address space in accordance with the policies documented in the Number Resource Policy Manual. For additional information, please see the ARIN IPv4 Countdown Plan.

What does “space available” really mean and why does it fluctuate?

"Available space" includes our current IPv4 inventory minus any returned, reclaimed, or revoked address blocks that may be in a hold status. This space fluctuates regularly based on outgoing new allocations and assignments, and incoming address space taken off its hold status. Please subscribe to the ARIN-issued mailing list to receive a daily report of addresses returned and addresses issued directly by ARIN or address blocks returned to ARIN's free pool and refer to our Statistics page for historical stats and monthly updates.

Why is some IPv4 address space being “held” and how long will you hold it?

As part of the ARIN IPv4 Countdown Plan, the hold period on all returned, revoked, and reclaimed address space will decrease as we approach depletion. When ARIN has three /8s it will decrease from six to three month, and when ARIN reaches one /8 the hold period will be reduced to one month.

  • Returned addresses are those that the registrant voluntarily returns to ARIN
  • Revoked addresses are those that ARIN takes back due to non-payment of registration fees
  • Reclaimed addresses are those that ARIN takes back due to fraud, misappropriation, or business dissolution

During the hold period, the resources are deregistered in Whois. Resources are held to allow them time to clear any filters or to allow an organization with revoked resources ample time to pay its overdue fees. ARIN may also have these address blocks bogon tested by an external third party during this hold period. Bogon testing is the process of probing networks to see if they will accept route announcements from the IP address range being tested.

Will ARIN now attempt to recover unused IPv4 address space, particularly the legacy space that is not being routed?

Even the successful return of more /8s would not significantly increase the lifetime for IPv4. Despite the small gains, the RIRs continue working on these issues and exploring all possible actions in this area.

Does IANA depletion change ARIN Internet number resource allocation policies?

IANA depletion triggers or impacts several policies:

    • Triggers NRPM 4.1.8, which limits requests to a single prefix once every three months while supplies last. This policy also establishes the rules for a waiting list. This is in case organizations want to wait for a larger allocation than ARIN is able to make at that point in time.
    • Impacts NRPM, which reduces the amount of address space that ISPs can request from a twelve-month to a three-month supply.
    • Impacts NRPM 4.10, which sets aside a contiguous IPv4 /10 block to facilitate IPv6 deployment.

What happens when ARIN runs out of IPv4 address space?

It’s inevitable that there will be some organizations that will still want/need IPv4 address space after the ARIN resource pool is depleted. ARIN’s Specified Transfer Listing Service (STLS) provides a way for organizations to either advertise their available IPv4 address space or contact an organization with space to arrange a transfer using section 8.3 of ARIN’s NRPM. Similarly, if organizations have or are in need of IPv4 address space and have contacted an organization with reciprocal inventory or need, they are welcome to conduct a transfer under section 8.3 of ARIN’s NRPM without utilizing the STLS.

Per NRPM 4.1.8, if ARIN does not have sufficient inventory to fulfill a qualified IPv4 request, the requesting organization may choose to be placed on a waiting list of pre-qualified recipients. This waiting list will specify both the largest block the organization is approved to receive and the smallest block the organization will accept. As address blocks become available for allocation, ARIN will fulfill waiting list requests on a first-come, first-served basis, subject to block size availability and re-verification of an organization's eligibility. For additional information, please visit the Unmet Request Waiting List page.

You told me you can’t fill my request, but the available address space listed is larger than what I requested. What is going on?

The total IPv4 address space listed as available is shown in aggregate. Your request could not be filled because it is larger than any continuous address range that ARIN had available for allocation at that point in time. NRPM 4.1.8 stipulates that after IANA IPv4 depletion, ARIN will issue IPv4 address space in a “single, continuous range of addresses.” This means you may request one single portion of address space (organizations can return and request more once every three months).

Does this impact my ability to get IPv6 address space?

We have plenty of IPv6 address space. You can request and get IPv6 address space from ARIN in accordance with the policies in the NRPM, just as you did prior to IANA IPv4 free pool depletion. ARIN largely considers your IPv4 and IPv6 holdings separate when reviewing requests. Some IPv6 policies do refer to IPv4 policies when describing points of criteria, however IPv4 depletion does not impact your ability to get IPv6 address space from ARIN.

What is the status of the Interop /8?

ARIN accepted Interop's returned space in October 2010. Following the ICANN Board adoption of Global Policy Proposal - IPv4–2011, the ARIN Board of Trustees directed ARIN staff to return to the IANA the IPv4 address blocks that have been voluntarily returned to ARIN in recent years. For additional details, please view the listing of all the address blocks that were returned to the IANA.