[ale] IPv6 routing issues

[Michael H. Warfield]

On Fri, 2009-09-04 at 10:02 -0600, JK wrote:
> Michael H. Warfield wrote:
> > On Thu, 2009-09-03 at 09:53 -0600, JK wrote:
> >> Hi ALE,
> > 
> >> I installed the freenet6.net IPv6 tunnel client (tspc) on my Ubuntu box,
> >> and it establishes a tunnel successfully using my account credentials.
> >> However, I can't get a reply from ping6'ing any remote host -- "No
> >> route to host".
> > 
> >> So, hmm, I guess it's a routing problem.  And in fact "ip route list"
> >> reveals no IP6 routing info.  Google is rife with advice to set up a
> >> default IP6 route via the tunnel device:
> > 
> >>    ip route add ::/0 dev sit1
> > 
> >> But this does not help at all.  Further, the route does not even seem
> >> to be added (even though the "ip route" command succeeds): subsequently,
> > 
> >>    ip route list dev sit1
> > 
> >> returns no entries, and a plain "ip route list" shows nothing that
> >> looks like the IP6 route I just added.
> > 
> > 	Try "ip -6 route ls".  Without the -6 it's only going to show you the
> > v4 routes.
> > 
> > 	Sounds like IPv6 has been initialized properly OR you have IPv6
> > forwarding enabled.  It's a peculiarity (a deliberate peculiarity) that
> > the kernel will not honor the IPv6 default route if IPv6 forwarding is
> > enabled.  This was, ostensibly, to prevent the accidental routing of
> > link-local, site-local, and scoped multicast beyond their designed
> > scopes.
> > 
> > 	Try this instead: "ip -6 route add 2000::/3 dev sit1"
> > 
> > 	See if that works any better for you.
> 

> Nope.  I also disabled IP6 forwarding, and no joy :-(  Plus I do
> actually want this machine to be a router.

	That's not a problem.  Leave forwarding on.  It really just means you
can not use the default route and you need the 2000::/3 route down the
sit1 device.  That route is the entire global unicast space.  You're not
allowed to route anything outside of that down the sit device anyways.
I think the last time I played with tspc, I actually had to modify the
up script to add the 2000::/3 route instead of adding a default route.
I've never looked at the Debian / Ubuntu scripts for tspc.

> "ip -6 neigh list" returns nothing, even when my tunnel is up. Should
> this worry me?

	No not really.  That's really the IPv6 equivalent of the arp tables and
"arp -a".  If you had other machines on your local ethernet that were
responding on IPv6, they would show up there.

> Also, the v6 address on the sit1 interface is 2001:blah:blah::blah/128,
> which seems to indicate that maybe I didn't get the /64 I (thought I)
> asked for?  Their info page makes a distinction between the prefix
> assigned to the tunnel vs the "delegated" prefix, but I don't understand
> the distinction.

	That's not a problem either.  That's all you should have on that p2p
link.  You should see your /64 show up on your eth0 interface.  The tspc
app and scripts should set that up for you automatically.

> Probably I need to read more :-/

	Run the following and post them.  Sanitize them if you like,
personally, I don't care about mine, people can look up my v6 addresses
in my DNS just like all my v4 address.  My space is 2001:4830:3000::/48
from OCCAID.

	Run the following.

	ip -6 addr ls
	ip -6 route ls

	I'm a Fedora / rpm / sysv init person so it may be a little more
challenging for me to figure out whats wrong on that Ubuntu box.

> Thx,

> -- JK

	Regards,
	Mike
-- 
Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
   NIC whois: MHW9          | An optimist believes we live in the best of all
 PGP Key: 0x674627FF        | possible worlds.  A pessimist is sure of it!
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