> -----Original Message----- > From: Vlad Yasevich [mailto:[EMAIL PROTECTED] > Sent: Wednesday, October 25, 2006 10:07 AM > To: James Carlson > Cc: [email protected] > Subject: Re: address selection and DHCPv6 > Why do you want to distinguish between DHCP, manual, and > autoconfigured addresses? If they are all of the same scope, > then the longest prefix match _should_ give you the best one > to use. If they are of different scopes, the scope rule will > select the better address. > > Method of configuration doesn't really play any role here...
Yes, they do, especially when different types of addreses are configured on the same Interface/prefix. For example, you can have a host with mannually configured address 2001:db8:1:1::1 and a stateless autoconf address within the same prefix: 2001:db8:1:1:aaaa:aaaa:aaaa:aaaa As the manualy configured ones are supposed to be more stable than the autoconf ones (they do not depend on a piece of hardware) you might want to use them in access list, firewalls,... They might also be the only one populated in the reverse DNS tree... So, yes, there is a reason to prefer a configured address over a stateless autoconf one. Same argument applies with DHCPv6 configured addresses. I know you can play with the A bit in the RA to prevent hosts from doing stateless autoconf, but this is a prefix wide directive, it lacks the host (or group of hosts) granularity. On some OS you can disable stateless autoconf, but this can be cumbersome. What is proposed here is essentially a fail safe mechanism that will make sure that if you combined the different address configuration types on a subnet, the basic mode of operation is predictible. - Alain. -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
