We are by no means out of IPv4 addresses. The next step is that all of the entities who needlessly snapped up /8 space early on and sat on it for so long will be selling it off. The list includes GE, Xerox, IBM, HP, Apple, MIT, Ford, Halliburton, Prudential Insurance, Bell-Northern, Merck, Eli Lilly, the DoD/military (who has 13), USPS, and CSC. Just half of this space is 234m IPv4 addresses.
Sigh... this idea has to get thrown out every time there's an IPv4-exhaustion discussion. I guess I'll be the one to do the public service of debunking it this time.
* You can assume that each of the /8s have plenty of infrastructure relying on them, meaning $millions in migration costs. Do you think that the holders will just give them up tomorrow, or do you think its more likely they'll sick some lawyers on the problem? So even if you CAN get them back it'll take years.
* For each /8 you successfully extract this way, you buy the world mere WEEKS of time.
IPv4 allocation isn't completely efficient -- we all know that. The real problem, however, isn't efficiency. 2^32 is just too small of a number.
Also, remember that some of those large companies are USING those /8's internally. No private addresses, just unreachable /8 public IPs - the way the internet is supposed to work.
We need to stop beating a dead horse and start deploying AAAA and v6 across the board. We used to only have 3 network sizes too (/8, /16, and /24), but we managed as an internet community to get rid of classful crap and move onto VLSM and CIDR.
Although the /8s have an entire infrastructure relying on their current situation, it is not unthinkable that the economical advantage of making subsets of their space available to third parties will become more attractive than just letting it sit idle. It might even justify the migration costs. So maybe we'll see parts of IBM, Apple and HP transform to IP/DNS providers.
Apart from that, it's not a question of having the /8s 'give back' IP adresses -- it's about them monetizing their available IPv4 space, out of their own volition.
Whether that relieves the IPv4 shortage for weeks or months doesn't really matter. What matters is what value they can extract from it.
The "IPv4 marketplace" idea has serious issues of its own, though:
1. it's ARIN (and, I think, other registrars) policy that you do not `own' your assignments in any legal sense. So if you sell them you may be committing fraud. If the deal goes bad it's not clear what the legal recourse would be. This is just a flipside of the "take back the /8s" problem: it gives too much for the lawyers to do.
They might even collide: suppose a large company with a /8 (say, Haliburton) decides to open a IPv4 marketplace. In response, ARIN says "well its clear you have more IP space than you need, so we're taking back your allocation effective next month" Now who has the rights to those IPs: the people who paid Haliburton for them, or those that got them in new assignments from ARIN?
2. Just having an IPv4 address isn't useful if it isn't routable. To split up a /8 into tiny salable bits means that all of the backbones need to update their BGP route prefix filters.
If this were done under the auspices of ICANN this wouldn't be a big problem at all: if ICANN says that the allocation policy for an address range has changed then all of the big players will follow suit. (There can be a few remaining routing issues for a new /8 on the periphery but they tend to get sorted out fairly quickly)
Would a similar announcement from Halliburton have the same effect? Doubtful, especially if it is done in opposition to ICANN's wishes. So probably any IPs "bought" in this system won't actually be routable.
3. Related: even if there was a healthy, 100% legal marketplace for IPv4 space it could only be practical if they were bought and sold in large chunks exclusively. If everybody who wanted some space for their company had to buy their own /28, the global BGP routing table would completely explode.
The only workable marketplace would be at the ISP level.
4. The registries are all united in wanting IPv6 deployed. Having companies making big profits selling their lucky IPv4 windfalls means that there would be deep-pocketed people with a vested interest in stalling IPv6 even more... after all if IPv6 were widely deployed the value of `their' IPv4 addresses would plummet.
Now it is true that if the IPv4 situation becomes dire enough, some of these players might decide to suddenly get into the hosting game and put more of their IP space to use. For instance, Apple has a /8 and just built a HUGE datacenter.. maybe they want to do their own version of EC2? The idea is a little odd but maybe not unthinkable
