If you are a mobile Internet subscriber in Asia, you may pretty soon, according to Cricket Liu, vice president of architecture at Internet software vendor InfoBlox. APNIC (Asia-Pacific Network Information Centre) kicked off the final allocation of IPv4 addresses to the regional registries because it needed two new blocks of addresses to satisfy fast-growing demand in the region. Mobile phones are the first Internet devices for many people in developing parts of Asia, and assigning IP addresses to those is part of the reason for the crunch. When mobile operators run out of IPv4 addresses, they will have to resort to selling phones with only an IPv6 address, Liu said.
5. What would happen if I only had IPv6 and tried to go to an IPv4-only website?
In the worst case, you wouldn't even get the familiar "server not found" message, according to Liu. This type of warning, also known as a "404" message, comes from the Web server of an existing domain that no longer hosts the page you're looking for. Without a usable IP address, no Web server can be reached. "It would probably just give you some sort of a network error," Liu said. Leo Vegoda, manager of number resources at the ICANN, said the message you receive will be up to your browser vendor.
6. So, would IPv6 cut me off from the Web?
In reality, you would probably get to see the website anyway, according to Liu of InfoBlox. Service providers are evaluating a variety of tools for delivering IPv4-only content to IPv6-only clients. The most common one is a network address translation technique called NAT64, which can run on an appliance attached to a service provider's network. When a name server can't find an IPv6 address associated with the website that the user wants to visit, a NAT64 appliance can take the host's IPv4 address and encapsulate it within an IPv6 address, creating something that the IPv6-only client can understand. Similarly, that appliance could allow users with different types of IP addresses to send e-mail to each other.
7. What if a site goes IPv6 and I'm still on IPv4?
That's not likely to be a problem, at least in the next few years, because when companies adopt IPv6, most of them will use a "dual-stack" configuration, experts said. Dual network stacks contain all the software needed for communication with both IPv4 and IPv6 systems. When a client requests an IP address of either kind that's associated with a given domain, they can get one. This is the system that's really in place at most organizations that are using IPv6 today. "It's not common to support v6, but if you do support v6, then it's very common to run dual stack," Liu said.