Is There Life in IPv4 After All?

Carl Weinschenk

The debate about Internet Protocol version 6 (IPv6) has never been about whether it is needed. The need has been an assumption of every post and article on the subject, including those in the mainstream media. The topic generally is what it will take to get industry to truly commit to the new addressing scheme.

A study released last week by ZScaler is precisely what IPv6 proponents don't need. It suggests that the certainty of the new addressing schemes need might not be ironclad after all.

The wording in this story in The Register is a bit vague, but the idea is that the address area being exhausted is not the entire universe of IPv4 addresses, but a subset. This is the key quote in the story is attributed to Mike Geide, senior security researcher for ZScaler:

From Zscaler's large and diverse customer base and our billions of web transactions serviced, we are able to infer that the large amount of "untouched" IP space from our customers is a good representation of Internet as a whole. In other words, much of the IPv4 space is not utilized to provide public, Internet-facing services or content.

The article doesn't have anything more about the possibility that the shortage is overhyped and any prognostication of the Chicken Little recriminations that will follow if this theory proves correct. The story does, however, provide good background on the overall situation.

A survey by gogo6 is not quite as glitzy as a finding that the need for IPv6 is way overhyped, but interesting and significant in its own right. The company, which bills itself as a social network for IPv6 pros, took a look at who is preparing-and who is ignoring-IPv6. The most important finding is that 70 percent of respondents are upgrading their own home networks. The next most active subgroups are fixed broadband networks and research/educational networks, with a scant 8 percent each.

To some extent, this is understandable: A social network made up of adherents of something -- composing haikus, bungee jumping or engineering IPv6-represents a population that is more likely to participate in that endeavor than the populace at large. It also is well known that the companies for which these folks work are dragging their corporate feet on IPv6. So the two groups are bookends, and the disparity is a concern, but not a surprise.

Two posts take a look at the challenges of IPv6. Irwin Lazar reports on FutureNet conference, which took place last month in Boston. Lazar writes that the conference looked at the issue of scalability of routers in the transition from IPv4 to IPv6. There are yellow flags to which attention must be paid. Writes Lazar:

Meanwhile, most major Internet service providers have begun to implement IPv6 within their networks to solve the address shortage problem. But IPv6 migration creates new and possibly more severe problems as Internet routers already taxed with maintaining rapidly growing route tables now must cope with the addition of IPv6 routes (most providers are using a "dual-stack" approach of running both IPv6 and IPv4 at the same time), and inevitable continued fractioning of the IPv4 address space.

There also are security questions. The pernicious element is that the adoption by the industry of an IPv6 framework opens organizations to security issues whether or not the particular company itself is using the new procedure. Some current security gear can't assess IPv6 data flows, so their presence poses a risk even if they are not enabled.


The move to IPv6 is complex and presents many risks. The most important step, then, is to ensure that it truly is necessary one.

Add Comment      Leave a comment on this blog post
Jun 2, 2010 12:05 PM Alessandro Manica Alessandro Manica  says:

If you look at the Hilbert Curve of the Internet at page 4 of the ZScaler report here:

and compare it with the map of the internet that you can find here:

you will notice that the unused blocks are mainly the ones assigned already more than 15 years ago to various institutions and to ARIN.

For what concerns ARIN, IANA has already collected 7.55 /8 Blocks of scraps which should be assigned after the last officially unallocated block will be given out in late 2011, so you can forget about getting more out of ARIN's blocks.

In regard of the blocks officially allocated by HP, DEC, Ford and all other grey marked squares, except for one AT&T block, they do look unused.

But even if you are able to reuse them by forcing the companies to relocate their servers, which does cost a lot of money and time to perform, they sum up to thirty-eight /8 blocks.

Given a consumption of approximately twelwe /8 Blocks a year, this would mean that by reutilizing those blocks we would be able to delay the total exhaustion of the IPv4 address space by little more than three years.

So the conclusion is: YES, we definitely will need IPv6.


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