Re: Enabling SLAAC for IPv6 by default

[Roy Marples <roy%marples.name@localhost>]

On 25/09/2018 18:07, Andy Ruhl wrote:
> Sorry for the possible hijack.
>
> Can someone educate me or point me to documentation on how NetBSD (or
> possibly anything else) uses these various IPv6 addresses from
> "myself" outward?
>
> I play with IPv6 a little. I set up ipsec between 2 machines using
> their SLAAC address which stayed stable. If I set up some other
> listener I probably would want to use that address as well, or some
> other permanent address.
>
> But if I want to, say, browse the internet from one of those machines,
> I think I want the outbound connection to be initiated from a
> temporary address.
>
> How does the OS decide?

I've not checked extensively, but each time a new outbound connection is 
made without specifying an address to send from, the OS will select the 
newest address with the longest matching prefix for the destination.

The only way to affect this is to set net.inet6.ip6.prefer_tempaddr = 1 
where it will always try to use a temporary address.

Roy