IPv6 with Zen in the UK

[Mike Crowe <mac@mcrowe.com>]

Does anyone happen to have a working configuration using Debian pppd to
connect to Zen Internet in the UK with working IPv6? It looks like IPv6 is
expected to run over the IPv4 PPPoE connection. IPv4 is all working fine.

I added:
 +ipv6 ipv6cp-use-ipaddr
to the provider file in /etc/ppp/peers and the pppd output looks promising:

Apr  1 13:33:27 deneb pppd[117669]: rcvd [IPV6CP ConfReq id=0x1a <addr fe80::827f:f8ff:fe74:b4f3>]
Apr  1 13:33:27 deneb pppd[117669]: sent [IPV6CP ConfAck id=0x1a <addr fe80::827f:f8ff:fe74:b4f3>]
[...]
Apr  1 13:33:27 deneb pppd[117669]: rcvd [IPV6CP ConfAck id=0x1 <addr fe80::4147:9ae5:df4d:be66>]
Apr  1 13:33:27 deneb pppd[117669]: local  LL address fe80::4147:9ae5:df4d:be66
Apr  1 13:33:27 deneb pppd[117669]: remote LL address fe80::827f:f8ff:fe74:b4f3

and I can ping the remote link-local address successfully. I see occasional
router advertisements, but they have a reachable time of 0ms.

If I drop the "ipv6cp-use-ipaddr" then I get different link-local addresses
for both the local and remote, but the router advertisements from the new
remote still have a reachability time of 0ms.

I tried manually assigning an address from the WAN /64 that Zen gave me to
the ppp interface and setting the default route to the remote link-local
address, but I never got any responses from anything out on the real IPv6
Internet.

I'm starting to wonder whether Zen really did turn on IPv6 support on my
line correctly since I couldn't make it work with the router they sent me
either.

Thanks.

Mike.