[6bone] IPv6 via NAT - problems

[Pekka Savola]

On Mon, 21 Oct 2002, Jeremy Worrells wrote:
> Good afternoon, 6bone!
> 
> I am a career sysadmin with a great interest in IPv6. I am trying to get a
> small IPv6 network running at home, using Freenet6 and a FreeBSD 4.6.2
> server. I have the software installed, and the interface comes up. However,
> I cannot get a ping6 or traceroute6 to supply any answers. My Cisco 678 DSL
> router is set up to NAT all protocol 41 and TCP port 4343 traffic to my
> FreeBSD server. Here is the output from a tcpdump on another machine on the
> LAN:
> 
> 11:33:50.929054 worrells.dsl.xmission.com > www.freenet6.net:
> jworrells.tsps1.freenet6.net > 3ffe:505:2008:1:2e0:18ff:fea8:4533: icmp6:
> echo request (encap)
> 11:33:51.358566 www.freenet6.net > 172.16.0.4:
> 3ffe:505:2008:1:2e0:18ff:fea8:4533 > jworrells.tsps1.freenet6.net: icmp6:
> echo reply (encap)
> 
> It appears that the packets are going to the right places, but are for some
> reason not getting to the IPv6 stack. Here are my interface details:
> 
> fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         inet 172.16.0.4 netmask 0xffffff00 broadcast 172.16.0.255
>         inet6 fe80::203:47ff:fe98:96f5%fxp0 prefixlen 64 scopeid 0x1
>         ether 00:03:47:98:96:f5
>         media: Ethernet autoselect (10baseT/UTP)
>         status: active
> gif0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1280
>         tunnel inet 166.70.27.6 --> 206.123.31.114
                      ^^^^^^^^^^^

there's probably a check in the decapsulator that the packets must come 
from this/to this address, perhaps you should try changing it to 
172.16.0.4 ?  Else you have to hack the kernel source, I'm afraid.

Ugly way to get IPv6, but if it works.... :-)

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords