v6 & DSL / Cable modems

TJ trejrco at gmail.com
Sat Feb 7 16:54:52 UTC 2009

>What most people do of course is VRRP.

Sure, or HSRP or GLBP ... all still doable.

>Barring that, you just specify multiple default routers, and the client
>select the router that still responds to ARP.  But support for this is not
>universal, so.

Indeed, not universal and in fact default behaviors vary wildly.

>When that isn't available, what I have done in the past here is to use the
>DHCP server to give out a default router option that is sorted according to
>the DHCP relay agent that was used to reach the server (keyed on giaddr
>The net result is that the client uses the default gateway which it used to
>reach the DHCP server, and so will automatically receive an updated value
>that router fails, as part of DHCP lease rebinding (it will reach the
>via the alternate router).

Which I think is pretty slick.
OOC - between the "router fails" and "I renew/rebind my address", is the
host down and out?
	So you are accepting either a noticeable outage or tweaking your
lease times, yes?

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