Web running out of addresses
Some
sites and service are moving to IPv6, but the majority remain wedded to IPv4,
after the last of the unclaimed IPv4 addresses were handed over to regional
registry bodies. Stephen Lawson explains.
Support for IPv6 has grown by almost
20 times in the past year, but most websites still can't be reached without
IPv4, the current Internet Protocol, which is running out of unclaimed
addresses. The number of subdomains under .com, .net and .org that support IPv6
increased by about 1,900 percent in the year leading up to October 2011,
according to an automated sampling of subdomains by Measurement Factory, The
study, which was sponsored by IPv6 software specialist InfoBlox, used a script
to automatically sample 1 percent of the subdomains under the three well-known
top-level domains.
IPv4 allows for only about 4 billion
addresses, whereas IPv6 has a near-unlimited supply. The internet Corporation
for Assigned Names and Numbers (ICANN) assigned the last of the unclaimed IPv4
addresses to regional registry bodies earlier this year. Some enterprises and
service providers are making a gradual transition to IPv6 using dual software
stacks, but experts expect users eventually to come to the Internet without
IPv4 addresses. They will need pure IPv6 communication, which most operators of
websites can't offer today.
Last month, 25.4 percent of
subdomains under .com, .net and .org supported IPv6, up from just 1.27 percent
a year earlier. However, the long-awaited IPv6 future may not be as close as it
sounds from that statistic.
All the figure means is that a domain
name system (DNS) server can point to those subdomains using IPv6. If a user
with an iPv6-only device tries to go to a website, for example, the site's
registrar can match up its URL with an IPv6 address and kick back an answer to
the web surfer, said Cricket Liu, vice-president of architecture at InfoBlox.
GoDaddy
leads the way
Most of the dramatic boost in the past
year came when GoDaddy, one of the world's largest domain registrars, made its
DNS work with iPv6. GoDaddy claims its DNS service has more than 30 million
customers. Had it not been for GoDaddy, the number of subdomains supported
would have grown by a bit more than double, to about 3 percent, according to
Measurement Factory.
But for now, most of those DNS
requests wouldn't take an IPv6-only user to an actual web page, because less
than 1 percent of all subdomains surveyed had IPv6-enabled web servers.
Likewise, there were very few IPv6 email servers. Just over 2 percent of zones
were served by IPv6-compatible mail servers.
The good news is that many more
operators of websites can serve IPv6 visitors once they have an lPv6-compliant
web server, Liu said. Along with GoDaddy, Measurement Factory cited three other
major registrars - Gandi and OVH in France, and Active24 in the Czech Republic
- that adopted IPv6 during the period.
GoDaddy has said it plans to extend
its IPv6 strategy soon by supporting the new protocol on its website-hosting
service. Companies that rely on GoDaddy instead of operating their own web
servers will then be able to run an IPv6 site.
The Measurement Factory found France
leading in IPv6 adoption, with 57 percent of subdomains
in France reachable by IPv6, followed by the US with 42 percent and the Czech
Republic with 36 percent. But its scope was limited by examining only .com,
.net and .org. For one thing, this left out subdomains that are under
country-level domains in Asia, where a more severe shortage of IPv4 addresses
has led to strong government efforts to push IPv6 in some countries.
The sample also overlooked other
top-level domains where IPv6 has been more widely adopted, such as the .gov
domain of the government and the .edu domain used by universities, said Nav
Chander, an Internet infrastructure analyst at IDC, However, the move to pure
iPv6 networking remains slow. "There's still very little IPv6 usage,"
he said.
