Using and Migrating to IPv6
The Internet is facing a slowly-unfolding crisis. The Internet Assigned Numbers Authority (IANA) ran out of assignable IP address blocks in April of this year. APNIC ran out of its allocation in April as well. The other regional registries have only a few years' worth of addresses to issue. There is an obvious need for the larger address space that IPv6 provides, yet adoption remains low. Shumon Huque's training session on Tuesday afternoon aimed to fix that.
Many IPv4 concepts have IPv6 analogues, although the two protocols are not compatible. There are some differences, however. For one, there is a greater emphasis on the client self-configuring. Machines that do not have static addresses set can obtain configuration via Stateless Address Autoconfiguration (SLAAC) or with DHCPv6. This does make it more difficult to control what devices can connect to the network. Some organizations prefer to use DHCPv6 because it allows pre-creating DNS records for the address pool. Automated configuration makes heavy use of ICMP, so it's important to be judicious when crafting firewall rules.
Most operating systems have out-of-the box support for IPv6, and many have it turned on by default. Major applications have IPv6 support as well, including web browsers, IMAP servers, and instant messaging applications. (A large, but incomplete list of applications with IPv6 support can be found at http://www.ipv6-to-standard.org/) So where's the holdup? There seems to be a lack of support for IPv6 in consumer-grade modems and routers, and lSPs and CDNs are slow to roll IPv6 to customers.
Comcast and Time Warner have begun limited IPv6 rollouts to friendly customers, and Akami claims to be the first CDN with IPv6 support. In the meantime, people interested in using IPv6 can set up tunneling through 6to4 or Taredo, or with a managed tunnel like the ones provided by Hurricane Electric, Freenet6, and Sixxs.
IPv6 adoption will be forced eventually, as the remaining IPv4 addresses are taken. But IPv4 will continue to coexist with IPv6 for many years to come. There are still issues to work out with IPv6, including user and admin training. Additionally, DHCP failover will need to be added to DCHPv6 before some sites will be willing to make the transition. In addition, network appliances like intrusion detection and intrusion prevention services will need to mature their IPv6 support.
Until then, expect to see IPv6 training remain a LISA staple.