Re: 2.4.21+ - IPv6 over IPv4 tunneling b0rked

[Anand Kumria <wildfire@progsoc.org>]

On Fri, 11 Jul 2003 02:08:20 +1000, Pekka Savola wrote:

> On Fri, 11 Jul 2003, YOSHIFUJI Hideaki / [iso-2022-jp] ^[$B5HF#1QL@^[(B
> wrote:
>> In article <20030710154302.GE1722@zip.com.au> (at Fri, 11 Jul 2003
>> 01:43:03 +1000), CaT <cat@zip.com.au> says:
>> 
>> > With 2.4.21-pre2 I can get a nice tunnel going over my ppp connection
>> > and as such get ipv6 connectivity. I think went to 2.4.21 and then to
>> > 2.4.22-pre4 and bringing up the tunnel fails as follows:
>> :
>> > ip addr add 3ffe:8001:000c:ffff::37/127 dev sit1
>> >  ip route add ::/0 via 3ffe:8001:000c:ffff::36
>> > RTNETLINK answers: Invalid argument
>> 
>> This is not bug, but rather misconfiguration; you cannot use prefix::,
>> which is mandatory subnet routers anycast address, as unicast address.

I'm the other end of this link, so I'm wondering how this is a
misconfiguration. RFC3513 2.6.1 suggests to me that
3ffe:8001:c:ffff::36/127 is the router address (my end) and the other
side should be 3ffe:8001:c:ffff::37/127.

> While technically correct, I'm still not sure if this is (pragmatically)
> the correct approach.  It's OK to set a default route to go to the
> subnet routers anycast address (so, setting a route to prefix:: should
> not give you EINVAL).
> 

Both Yoshifuji and yourself suggested that /127 isn't the way to go and
that this is something v6ops ought to take up. I had a quick look at the
v6ops IETF group and nothing struck me.

What would you recommend I look at to see why /127 is a bad idea or /64
is a better idea than /127?

Thanks,
Anand