IPv6 tunnel

Felipe Alfaro Solana felipe.alfaro at gmail.com
Sat Jan 20 11:11:08 UTC 2007

On 1/18/07, Brian Lunergan <ff809 at ncf.ca> wrote:
> Morning All:
> Tried setting up firestarter and ran into a problem with location. Only gave me
> the option for IPv6 tunnel with a device code of Sit0 (or something very close
> to that). When I started the interface and logged on to the net it did pick up
> on ppp0 being present and active but it still would not start because it didn't
> see the tunnel as an active device.

sit0 is the Linux name for 6to4, a non-explicit way of transmitting
IPv6 packets over an IPv4 domain. The idea is that the 2002 prefix is
appended to the public IPv4 address of your border router creating a
special IPv6 prefix. Whenever any IPv6 packet arrives at that border
router with a 2002:: prefix, the IPv6 packet is automatically
encapsulated over an IPv4 packet whose destination address is the
remaining part of the 2002:: IPv6 prefix, and the IPv4 source address
is that of the border router.

> Did a short google on the term and IPv6 tunnel seems to be something associated
> more with business and network setups. Is it something I need for a single home
> machine? If it isn't, what are my targets and hunting ground to disable and/or
> remove? If it is useful, what changes do I need to make to get it to a state
> that Firestarter will see it as an active device?

There are different ways of creating IPv6 tunnels, depending whether
they are explicit or non-explicit, for example, like 6to4, 6over4,
Teredo or ISATAP. However, it doesn't mean that IPv6 tunnels are a
business-only technology, although is true that domestic users won't
probably find any interest in IPv6 at the time being. The problem is
that most of the tunneling technologies are incompatible with NAT, and
thus makes it also difficult to use and set it up for residential or
domestic users.

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