[j-nsp] PFE-forwarded IPv6

[Jonathan Lassoff]

Excerpts from Truman Boyes's message of Tue Dec 22 04:17:22 -0800 2009:
> Can you post the relevant configuration from the box? I expect that the host is
> directly connect to the MX-960; and the interface that is facing the host is
> running RA; furthermore if you look at the routing table on the host, you will
> see a default route to the MX's link-local address?

Actually, I was testing with a Cisco Cat6k/Sup720 box downstream to test
the interoperability of the two routers, and also IPv6 on the Cat6k.

As a test to better understand what's going on, I attached a host
downstream from the MX960. I can ping and reach the MX's inet6 interface
just fine. I'm also setting my default route to go through the inet6
interface on the MX.  Pinging out to 2001:500:2f::f (f.root-servers.net)
through this interface causes the MX to return an ICMPv6 Unreachable
(Address unreachable) message.

However, there's a route on the MX to that destination:

--------------------------------------------------------------------------
jof at mx1.sfo2-re0> show route 2001:500:2f::f 

inet6.0: 2299 destinations, 2302 routes (2299 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

2001:500:2f::/48   *[BGP/170] 1w3d 20:24:53, localpref 100
                      AS path: xxxx xxxxx 3557 I
                    > to xxxx:xxx:xxxx:xx::1 via ipip.0
--------------------------------------------------------------------------

Here's the relevant configuration of interface "ipip":
--------------------------------------------------------------------------
jof at mx1.sfo2-re0> show configuration interfaces ipip 
unit 0 {
    tunnel {
        source xxx.xxx.xxx.xxx;
        destination xxx.xxx.xxx.xxx;
    }
    family inet6 {
        address 2001:xxx:xxxx:xx::2/64;
    }
}
--------------------------------------------------------------------------

Thanks for any help or insight you can provide.

Cheers,
jonathan