[radvd-devel-l] Advertise different router?

Mark Smith radvd at 02a76c927861ca7413a122f2a73a0d37.nosense.org
Thu Jun 2 19:01:51 EDT 2011

On Thu, 2 Jun 2011 14:35:29 +0200
Dyonisius Visser <visser at terena.org> wrote:

> On 2 June 2011 01:24, Mark Smith
> <radvd at 02a76c927861ca7413a122f2a73a0d37.nosense.org> wrote:
> >> I am running the M and O flags set in our Cisco sup720/msfc3 core to deliver the RDNSS information in the DHCP packets.
> >> I am also using the ipv6 dhcp relay destination command in the above Cisco config to request ipv6 DHCP addresses across VLAN's.
> >>
> >
> > I think this is a better set up. If you want to make more
> > service/application settings available via a new DHCPv6 option, the only
> > dependency you have is that the DHCPv6 server and the DHCPv6 clients
> > that are interested in the new option support it.
> >
> > Although there are currently only a couple of RA option equivalents to
> > DHCPv6 options, if you choose to go down the RA configuration path, in
> > addition to caring about which clients support the RA options, you also
> > have to care about which routers in your network can convey those
> > options and whether the clients will ever connect to them. In a large
> > network, with a variety of router models, that can be lots of checking.
> > If your some of your routers don't currently support the options you'll
> > also need to perform scheduled outages to upgrade their firmware or find
> > some other work around. This is Dyonisius's current problem. radvd
> > might be able to be used as a work around, but ultimately to
> > permanently eliminate these sorts of issues, a minimal stateless DHCPv6
> > client/relay/server setup is necessary.
> Just to be clear, I would like to set up an IPv6-only network, that is
> configured so that as much as possible devices can "just use it",
> WITHOUT ANY configuration.

No need to yell.

> I'm trying to figure out what (given the limitations of our old
> switch) is the Golden Way of doing things.
> I know that such a set-up will be subject to change now that IPv6 is
> gaining more support everywhere, but it might be an idea to document
> this properly.

RFC6106 - 

1.1.  Applicability Statements

   RA-based DNS configuration is a useful alternative in networks where
   an IPv6 host's address is autoconfigured through IPv6 stateless
   address autoconfiguration and where there is either no DHCPv6
   infrastructure at all or some hosts do not have a DHCPv6 client.  The
   intention is to enable the full configuration of basic networking
   information for hosts without requiring DHCPv6.  However, when in

Jeong, et al.                Standards Track                    [Page 3]
RFC 6106                   IPv6 RA DNS Options             November 2010

   many networks some additional information needs to be distributed,
   those networks are likely to employ DHCPv6.  In these networks, RA-
   based DNS configuration may not be needed.

   RA-based DNS configuration allows an IPv6 host to acquire the DNS
   configuration (i.e., DNS recursive server addresses and DNS Search
   List) for the link(s) to which the host is connected.  Furthermore,
   the host learns this DNS configuration from the same RA message that
   provides configuration information for the link, thereby avoiding
   also running DHCPv6.

   The advantages and disadvantages of the RA-based approach are
   discussed in [RFC4339] along with other approaches, such as the DHCP
   and well-known anycast address approaches.

> We all know that unfortunately for various reasons you need to run
> several daemon/services/protocols in parallel to achieve to seemingly
> simple goal.
> What comes to mind is a list of devices (windows7, MacOSX, Android,
> iOS) that can be selected, and then some advice of what is needed for
> usage.
> FYI: I will replace the clunky Cisco in 1-2 months, so this is all a
> temporary situation.
> The new switch will of course need to support all the needed features.
> -- 
> Dyonisius Visser
> System & Networking Engineer
> TERENA Secretariat
> Singel 468 D, 1017 AW Amsterdam
> The Netherlands
> T +31 20 530 44 88 F +31 20 530 44 99
> visser at terena.org | www.terena.org
> -- 
> radvd-devel-l mailing list  :  radvd-devel-l at litech.org
> http://lists.litech.org/listinfo/radvd-devel-l

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