Durand, Alain wrote: > > 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.
Well, here you depend on another piece of hardware, but that's not an issue. Also, this preference really depends on the usage cases. I can see scenarios, where I would rather use autoconfigured address over the DHCP or manually assigned one. > > 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. > The concern I have is someone else may find the above preference backwards and may want to always prefer autoconf addresses over DHCP or statically configured. This is a policy matter and you are proposing to encode it into the rules without ability to change. The rule set are basic postulates that enable best available communication. As an additonal step, the policy table is provided that allows for specific preferences. Is it flexible enough for you want? -vlad -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
