What Does Exhaustion Mean?
Trivially, the point of IPv4 exhaustion is the point at which the guaranteed-free-and-unused pool runs out and the current allocation mechanism comes to an end. Although the depletion of the free pool defines the technical point of exhaustion, it is not the depletion itself that is of primary importance. After all, if it were, we could simply declare a moratorium on allocations with immediate effect, to preserve the resource for some notional future requirements. Rather, it is the effect on the practices and procedures, within the RIRs and within the Local Internet Registries (LIRs), administrative and technical, that will practically define exhaustion. These practices, which have grown to fit around the current behavior of the addressing system, the free pool, and so on, will require urgent reform after exhaustion, as indeed will the RIR system in general.
Currently organizations use and require new addresses for essentially every IP-related additional deployment (for example, adding customers to a publicly numbered DSL service, adding extra Secure Sockets Layer (SSL)-enabled websites to a Web hosting service, and adding extra publicly reachable servers to almost any service).
It has been emphasized that this problem affects only the growth of organizations performing IP deployments . Although it is important to acknowledge the partial correctness of this statement, much about the postexhaustion state could undermine the stability of well-established advertisements and routes unless the transition is well-handled. It seems intuitively correct that those who received allocations before exhaustion will be unaffected by exhaustion turmoil.
What Are the Problems with Exhaustion?
The biggest problem is the simplest one: existing organizations whose business model or operations are solely predicated on an ongoing flow of IPv4 addresses will fail. This premise would seem an extreme, even theoretical, characterization, but the size of this category in the real world is larger than you might think. Numerous organizations are also in trouble, perhaps less predicated upon IPv4 than the others, but that—for example—might have financial or operational difficulty in making the post-exhaustion transition happen internally. They would also be placed at risk. Finally, there are those organizations that might rely on others to perform their transition correctly in order for them to continue effective operations: less directly at risk, but still probably affected.
The Consequences of Scarcity
Suppose for the moment that at the time of exhaustion, Internet-connected organizations have to fend for themselves, with no particularly well-defined industry strategy in place. We would then expect to see a broad movement within the industry to conserve precious public IPv4 address space. One obvious way for an organization to obtain more usable IPv4 space is to move previously publicly-numbered resources behind Network Address Translation (NAT) gateways. Other, less-legitimate sources of new addresses will probably also be explored, and these actions, combined with the generally uncoordinated changes, may well trigger the following negative consequences:
* Inability to measure clients, and difficulty of supporting them: As we see more layers of NAT within networks, it becomes gradually more difficult to establish who is actually connecting to you, and what problems they are having. Cookies are a partial solution for only one important protocol. Measurement becoming harder means that support costs will rise.
* Address-space hijacking: As organizations become more desperate for space, it is entirely feasible that they will begin to cast around for space not explicitly unavailable in order to meet their business needs. How widespread this practice would be remains an open question, but effective barriers to this behavior are not currently available. We would expect a general deterioration in the quality of routing.
* WHOIS database quality down: Coupled with layers of NAT hiding more and more networks from direct sight, transfers of address space (legitimate or otherwise) will cause the WHOIS database to become gradually less and less accurate, leading to...
* Distributed denial-of-service (DDoS) tracking trouble: Problems tracking DDoS attacks and abuse origins of all kinds make law enforcement and network operators equally unhappy.
* Connection quality down: Connection quality, in terms of connections that complete successfully and have tolerable latency, will go down as a function of client growth behind gateways.
* RIR billing model under pressure: The RIRs will need to find a new way to pay their costs or go out of business—gradually, but inevitably. Of course the RIRs, like every other organization, must serve a need, but they currently provide a large number of ancillary services not directly related to IP allocation, and those services would also be under threat.
* Consensus undermined: This consequence is possibly the most dangerous of them all. If a chaotic state of affairs is allowed to continue for too long, our very ability to make decisions as a community will be undermined as organizations abandon the RIR model that has failed them. We will have squandered, in a way, the foundation of trust that allows such ethical codes as we have developed in Internet operations to persist. That foundation will not be easily recovered.
PS: more reading…http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_11-4/114_eternity.html
I think comodo does not protect IPv6 protocol for the time being.