v6 & DSL / Cable modems

sthaug at nethelp.no sthaug at nethelp.no
Sat Feb 7 15:43:46 UTC 2009

> > I suppose you can individually configure every host to get itself
> > temporary addresses from RA announcements.  This isn't usually a
> > good default configuration, but OS implementation already seems to
> > be inconsistent on the default configuration here.  So we're back to
> > the IPv4 dark ages where you have to walk around to all the devices to
> > effect changes in policy (beyond prefix field contents).
> I'm not sure, but you seem to be implying that you need to configure  
> hosts to tell them to use RA or DHCPv6 to get addresses. My apologies  
> if this is not your intention.
> RA messages are always going to be sent by routers and received by  
> hosts, even if DHCPv6 is being used for address assignment.

This does not seem to be generally true:

- For the routers I am most familiar with (Juniper M/MX), you need to
explicitly turn on router advertisement to make the router perform this.
I.e. it is perfectly possible to have an interface with an IPv6 address
which does *not* send RAs.

- For the operating system I am most familiar with (FreeBSD), RAs are
*not* accepted by default if the interface in question is configured
with a static IPv6 address.

Both of these choices seem perfectly reasonable to me.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no

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