The American Registry for Internet Numbers (ARIN) can no longer satisfy requests for new IPv4 addresses and has started a waitlist for those who want more.
ARIN warned, in early June, that “It is very likely that we are already processing a request that we will be unable to fulfill [sic].”
On Monday this week it escalated the warning, suggesting “We expect to take registration actions this week that will activate ARIN’s policy for unmet requests.”
That warning has come to pass: the organisation activated the policy on Wednesday, after admitting to “... the approval of an address request that was larger than the available inventory in the regional IPv4 free pool.”
The unmet requests policy doesn't mean the IPv4 well is dry. ARIN still has small blocks of IPv4 addresses but warns it “may not be able to fulfill requests for IPv4 address space. This means we may be unable to fulfill a particular customer request for certain sizes of IPv4 address blocks, though not necessarily that we are out of IPv4 addresses entirely.”
ARIN's counter for unused IPv4 addresses says it has 0.00798 of a /8 address block up its sleeve. A /8 block offers 16,777,216 addresses, so it has about 133,882 addresses up its sleeve. While the organisation warns that its counter isn't very accurate for various reasons, the tone of its warning doesn't suggest it will find a few million addresses under the sofa any time soon.
IPv6 addresses are the obvious way out, because there's 2128 of those (or 340 undecillion, 340 with 36 trailing zeroes). But plenty of folk still operate IPv4 networks and with this whole internet thing proving not to be a fad there's demand for more.
ARIN administers IP addresses for "Canada, many Caribbean and North Atlantic islands, and the United States," so this isn't just a problem for the United States. If you are within ARIN's jurisdiction, it says “Organizations that need larger amounts of address space are encouraged to make use of the IPv4 transfer market for those needs." Plenty of IPv4 addresses are in private hands. Now looks like a decent time to offload them. ®