Subject: question: forcing IPV6 traffic down a IPV6/IPV4 tunnel
To: None <>
From: Dave Tyson <>
List: tech-net
Date: 03/09/2000 16:27:53
I am trying to finish setting up a PC running NetBSD 1.4T
(sources dated 22nd Feb) which will act as a IPV6 gateway router.

We have been provided with a IPV6 prefix and a tunnel to one of
the main UK gateways. I have configured the tunnel OK, however
I am at a loss as to how to force IPV6 traffic which is not
local down the tunnel - tried all sorts - nothing worked.

The basic details are:

                ne1 |  Agate (Nbsd 1.4)  | ne0
    ----------------|                    |--------------------  --------------------

ne1 is connected to our class B network, ne0 is connected to our IPV6
test network.

The IPV6 feed details are:

IPv6 prefix from JANET's "real" allocation:  2001:0630:0001::0/48.  

Tunnel details:

IPv4: (
IPv6:	PtP numbering is 2001:0630:0000:0003::0/64 is 2001:630:0:3:0:C46:B898:21/128
        statically routing your /48 at the moment

The tunnel came up fine and I can ping6 and get a response from both ends.

agate# ping6 -I gif0 -n ff02::1
PING6(56=40+8+8 bytes) gif0%fe80::200:1cff:fe50:2e --> ff02::1
16 bytes from lo0%fe80::200:1cff:fe50:2e, icmp_seq=0 hlim=64 time=1.282 ms
16 bytes from gif0%fe80::c46:b898:1b, icmp_seq=0 hlim=255 time=75.303 ms(DUP!)
16 bytes from lo0%fe80::200:1cff:fe50:2e, icmp_seq=1 hlim=64 time=0.816 ms
16 bytes from gif0%fe80::c46:b898:1b, icmp_seq=1 hlim=255 time=75.39 ms(DUP!)

The ne0 interface is configured with an IPV6 address and route6d is running
together with rtadvd on ne0. 

        address: 00:00:1c:50:00:2e
        media: Ethernet manual
        inet6 2001:630:1:0:200:1cff:fe50:2e prefixlen 64
        inet6 ne0%fe80::200:1cff:fe50:2e prefixlen 64 scopeid 0x1

        address: 00:00:1c:09:03:a7
        media: Ethernet manual
        inet netmask 0xffffff00 broadcast
        inet6 ne1%fe80::200:1cff:fe09:3a7 prefixlen 64 scopeid 0x2

gif0: flags=8011<UP,POINTOPOINT,MULTICAST> mtu 1280
        inet6 gif0%fe80::200:1cff:fe50:2e -> :: prefixlen 64 scopeid 0x10

What I need to achieve is to get IPV6 packets which are non-local routed
down the tunnel. Because the far end of the tunnel is statically routed,
the local route6d does not know where to send packets. What I need to do is 
set an IPV6 default route, however my all attempts so far have failed.

I can get the remote end to advertise routes down the tunnel, but I
guess it should be possible to manage without this. 

Any help appreciated.


Dave Tyson                      Phone: 0151-794-3731
Computing Services Dept         Fax:   0151-794-3759
The University of Liverpool     Email:	
Chadwick Building               Web: 
Peach Street                    Public Domain OS: see
Liverpool  L69 7ZF              
United Kingdom