Daniel Roesen writes:
On Thu, Nov 11, 2004 at 08:44:57AM -0800, Kevin Oberman wrote:
We have renumbered IPv6 space a couple of times when we were developing our addressing plan. (We have a /32.) Renumbering was pretty trivial for most systems, but servers requiring a fixed address were usually configured with an explicit prefix. This should not have been the case, but most people configured IPv6 addresses pretty much like IPv4 and specified the entire 128 bits. Of course, after a renumbering, this gets fixed, so those systems are usually OK the next time.
"specified the entire 128 bits"... how do you specify only part of it?
On Solaris, you would use the "token" option (see the extract from "man ifconfig" output below). You can simply put "token ::1234:5678" into /etc/hostname6.bge0. I assume that other sane OSes have similar mechanisms. 602 token address/prefix_length 603 Set the IPv6 token of an interface to be used for 604 address autoconfiguration. 605 606 example% ifconfig hme0 inet6 token ::1/64 607
What determines the rest?
The prefix advertised in prefix advertisements.
"fixed" as in "now using stateless autoconfig"? Fun... change NIC and you need to change DNS. Thanks, but no thanks. Not for non-mobile devices which need to be reachable with sessions initiated from remote (basically: servers).
The above mechanism solves this problem even with stateless autoconfiguration. Agree? I think it's an advantage if servers can get their prefixes from router announcements rather than from local config files. Sure, you still have to update the DNS at some point(s) during renumbering, but that can't be avoided anyway. -- Simon.