6bone access from behind NAT

[Pekka Savola]

On Thu, 6 Dec 2001, Michael Kjorling wrote:
> Also, I noted this in the 'ipv6 if' output:
> 
> > Interface 3 (site 1): 6-over-4 Virtual Interface
> >   uses Neighbor Discovery
> >   sends Router Advertisements
> >   forwards packets
> >   link-level address: 192.168.50.1
> >     preferred address fe80::c0a8:3201, infinite/infinite
> 
> Just a question to the gurus here - wouldn't the address be
> 2001:c0a8:3201::? http://www.6bone.net/6bone_6to4.html seems to imply
> this, if I read the text correctly: "A special IPv6 routing prefix
> (2002::/16) is used to indicate that the remaining 32-bits of the
> external routing prefix contain the IPv4 end-point address of a
> boundary IPv6 router for that site that will respond to IPv6 in IPv4
> encapsulation."

Packets to private addresses and their 6to4 equivalents MUST not be 
discarded.  You need a global address, otherwise you can't use 6to4.

Shipworm (see http://www.6bone.net/ngtrans/) is a solution for access with
private addresses, ie. in cases where your operator or your IPv6-incapable 
DSL/cable modem performs NAT.

-- 
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