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Scarcity of IPv4 Addresses

Patrik Fältström

My friend Kurtis writes in his blog some points he has been thinking of while discussing "when we run out of IPv4 addresses". In reality, as he points out so well, we will not run out. It will be harder to get addresses.

It is also the case that unfortunately people that push for IPv6 claim IPv6 will solve all different kinds of problem. Possibly also the starvation problems in the world, and the CO2 emission issues. But, in reality IPv6 is just like IPv4. It works like IPv4, it quacks like IPv4 etc. We will have the same problems with IPv6 as we have with IPv4. Except we will not have any addressing problems because of scarcity of addresses. The largest problems we have with IPv4 has to do with the fact that the overall topology of the Internet is changing. From a strict hierarchy to a mesh, and now to a hypercube. Everyone is connected to everyone else, and our routing protocols can not handle that. We need something new.

But "just getting some more bits" is not a bad thing. And should be enough for having more people looking into IPv6. What people have to remember though is that IPv4 and IPv6 are two different protocols, and too many people building networks today do not remember when we had more protocols than IPv4. We will need support for both IPv6 and IPv4 here and there in the network. We will need application level gateways and 6to4 "nat" boxes.

By Patrik Fältström, Technical Director and Head of Security at Netnod
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Related topics: IP Addressing, IPv6, Networks
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Re: Scarcity of IPv4 Addresses Kim Liu  –  Jul 25, 2007 2:22 PM PST

Yep.  It will be fun to see the rather in-grained hierarchial format of the IPv6 address meet the real world of non-hierarchial networks.  (Dual-homing, for instance.)

You are correct that we need "6to4 ''nat'' boxes", and frankly, we have for a while, but the pro-IPv6 crowd cannot allow themselves to think about those too much, even if they would speed IPv6 adoption.  The problem is if a useful "6to4" NAT was made, then one could do go through a "4to6" NAT from an IPv4 network, over an IPv6 backbone, then through an "6to4" NAT to get back to another IPv4 network.  On the face of it, such technology would speed up the adoption of IPv6 on the backbone, but conceptually it starts removing the need for "getting some more bits".  If you could solve the "6to4"/"4to6" NAT problems, you just stick two of them back-to-back, and you have solved the "4to4" NAT problems.

This seems to lead to the rabidly anti-NAT mentality, which is short-term depressing and long-term stupid.  The experience and concepts we are losing in forcing a single protocol, monolithic network are going to be costly in the long run.

Re: Scarcity of IPv4 Addresses John Curran  –  Aug 02, 2007 4:15 AM PST

...On the face of it, such technology would speed up the adoption of IPv6 on the backbone, but conceptually it starts removing the need for "getting some more bits".  If you could solve the "6to4"/"4to6" NAT problems, you just stick two of them back-to-back, and you have solved the "4to4" NAT problems.

Correct, and solving that problem in the absence of new functionality for IPv6 effectively means no need for IPv6.  (http://tools.ietf.org/html/rfc1669, from August 1994....)

/John

Re: Scarcity of IPv4 Addresses Kim Liu  –  Aug 02, 2007 7:11 AM PST

John Curran said:

Correct, and solving that problem in the absence of new functionality for IPv6 effectively means no need for IPv6.  (http://tools.ietf.org/html/rfc1669, from August 1994....)

Exactly.  Hence, this frequently leading to an anti-NAT mentality.

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