ICANN | ICANN Policy Update Background - Global Policy Proposal for Handling Recovered IPv4

IPv4 unallocated address blocks in IANA's pool continue to be depleted. A global policy has been proposed to allocate the remaining address blocks once a given threshold is triggered. The proposal is now a ratified policy and states that when there are five /8 blocks remaining in the IANA pool, one remaining block will be allocated to each RIR.

The approach is that IANA will serve as repository for IPv4 blocks returned by the RIRs and then allocate them to the RIRs according to need. Two phases are foreseen:

Initially, IANA just collects recovered IPv4 space from the RIRs, no smaller than /24 blocks (256 addresses).
From the moment that the IANA free pool is exhausted (i.e. when the last five /8 blocks have been allocated according to an already ratified global policy), IANA also handles requests from RIRs (maximum of two requests per RIR per year) for IPv4 address space and allocates according to need and availability. The minimum allocation to an RIR is a /24 and the maximum allocation is one tenth of IANA's available IPv4 address space. No allocation will take place in case the above maximum allocation is less than a /24. In this phase, IANA will also continue to receive any recently recovered space from the RIRs.