IP Address Blocks ARIN Issues From
ARIN IPv4 Address Blocks
ARIN (or its predecessor registries) have performed allocation and assignment of IPv4 address blocks from specific address blocks assigned by IANA. The list of IPv4 address blocks is available here on the IANA website.
ARIN’s free pool of IPv4 address space was depleted on 24 September 2015. As a result, we are no longer fulfilling requests for IPv4 addresses directly from a free pool. All approved IPv4 requests are placed on our waiting list for unmet requests. There are exceptions in special cases outlined by policy, such as:
- NRPM Section 4.10: This IPv4 block is dedicated to facilitate IPv6 deployment. Organizations may request a /24 of IPv4 address space to facilitate its IPv6 deployment if the following criteria are met:
- The applicant may not have received resources under this policy in the preceding six months, except to the extent that the applicant is requesting resources for a discrete network in respect of which it has not received any resources under this policy in the preceding six months;
- Previous allocations/assignments under this policy must continue to meet the justification requirements of this policy;
- Previous allocations/assignments under this policy must be utilized to at least 80% to obtain an additional allocation or assignment; the applicant must demonstrate that no other allocations or assignments will meet this need.
- An applicant requesting multiple allocations under this policy to support Multiple Discrete Networks, as defined under NRPM Section 4.5, may not receive more than the equivalent of a /21 of IPv4 address space in any one six-month period hereunder.
- NRPM Section 4.4: Micro-allocations can be provided to critical Internet infrastructure providers such as exchange point operators and core DNS service providers. We provide a list of micro-allocations.
ARIN also facilitates IPv4 transfers and maintains a listing of transferred address space.
Any resources allocated from a reserved pool created in Sections 4.4 or 4.10, or any other reserved pools created in the future, that become available for re-issuance will be returned to the reserved pool they were originally allocated from, regardless of the current level of each pool. Further, any other resources which become available for re-issuance will be prioritized for the replenishment of any reserved pool that falls below a running three-year supply, which is based on the previous three years of allocations from each pool.
Staff shall return groups of blocks to the pools in scheduled batches (staff shall set a reasonable schedule). Each available block in a batch shall be returned in order from largest to smallest to the pool which at that point has the lowest percentage of a 3-year supply for that particular pool.
ARIN IPv6 Allocation Blocks
List of IPv6 prefixes that have been set aside for ARIN to allocate from.
- 2600:0000::/12 
 ARIN is issuing IPv6 transitional technology blocks from 2602:0000::/16. For more information, please see NRPM Section 126.96.36.199.
ARIN IPv6 Assignment Blocks
List of IPv6 prefixes that have been set aside for ARIN to assign from.