A few weeks ago, I discovered the Internet was full. A Google search will find several articles on the topic. I found it somewhat entertaining to think of the Internet as full, because it's really far from full; content will forever be created and available at our fingertips. But, in the context of these articles, the Internet is full, not because it has no more capacity for content, but because it has no more capacity for additional users. Of course, all of us technical people know the real story …
We in the IBM i development community have known for years that the IPv4 address space was going to be exhausted. Prior estimates used to say 2014, then it was 2012, but here we are in 2011 and it has happened. Of course, i is prepared with support for IPv6.
IP Version 6 (IPv6) work started on i way back with the V5R2 release (V5R2 was available starting in 2002). There were many restrictions with the IPv6 support for the first few releases it was available on i--it was more of a development environment so that if you had your own sockets application, you could enable and test it for IPv6 support. None of the IBM i supplied TCP applications, such as FTP, Telnet, etc., had IPv6 support at that time.
In the 5.4 release, IPv6 support became consistent with the IPv4 support, with the initial restrictions removed. However, TCP application support for IPv6 was still lagging. While the TCP stack supported IPv6, the applications provided by IBM didn’t.
Finally, in the 6.1 release, many of the TCP applications were enhanced with IPv6 support, and in 7.1 that work is essentially complete--nearly all TCP applications that IBM provides are fully IPv6 enabled.
The 7.1 release provides the richest IPv6 support and is the first i release to be certified as meeting the current U.S. government IPv6 requirements. When you need to move to IPv6, 7.1 is the release that IBM recommends you use.