[Dnsmasq-discuss] Make RA_INTERVAL configureable? Deprecate old prefixes?

Simon Kelley simon at thekelleys.org.uk
Fri Jul 26 09:52:17 BST 2013


On 25/07/13 22:32, Uwe Schindler wrote:
> Hi,
>
> reading https://datatracker.ietf.org/doc/rfc6204/?include_text=1, the
> requirements for home routers are listed here:
>
> L-13:  If the delegated prefix changes, i.e., the current prefix is
> replaced with a new prefix without any overlapping time period, then
> the IPv6 CE router MUST immediately advertise the old prefix with a
> Preferred Lifetime of zero and a Valid Lifetime of the lower of the
> current Valid Lifetime and 2 hours (which must be decremented in real
> time) in a Router Advertisement message as described in Section
> 5.5.3, (e) of [RFC4862].
>
> This was my original proposal. I agree that this should be done by
> the PPP/WAN interface and the DHCPv6 cleint on the WAN interface, so
> the old prefix gets deprecated, but with current software available
> (ISC dhcpd does not work on PPP interfaces but would support that
> using a shell script applying the prefix delegation - and wide-dhcpc
> supports PPP interfaces, but it allows not to configure prefix
> delegation, so in deprecates addresses after PPP reconnect or a
> change of the prefix).
>
> So I would be very happy, if dnsmasq (as router advertisement daemon
> would provide support for this). Radvd does it - see DeprecatePrefix
> options in radvd.
>
> Uwe
>


Good find. It's not clear to me if this is a one-off advertisement, or 
if the advertisements need to be repeated, though the 2 hours stuff 
implies that it should be repeated. I'll have a think about how to 
implement this withing the existing code. A one-off advertisement should 
be quite simple, but repeated ones are more difficult.


Cheers,

Simon.



More information about the Dnsmasq-discuss mailing list