Problems with gif tunnels

[Jeremie Le Hen]

Greg,

> My understanding is that GRE is to IP as PPP is to SLIP: it allows
> multiple protocols to be encapsulated.  I've done some tracing with
> Ethereal, and the only difference is a four-byte header in front of
> the payload for GRE; in an IP tunnel, it's simply missing.  I've
> written this up in my diary
> (http://www.lemis.com/grog/diary-jun2005.html#8), along with the
> traces.

yes it's usually a simple four-byte header when doing a simple tunnel.
But from what I have read [1] and according to what Giorgos said,
it seems it can be a lot more longer, depending on the value of the
five first bits of the GRE header.

Enjoy your tunnel ;-).

[1] http://www.networksorcery.com/enp/protocol/gre.htm
-- 
Jeremie Le Hen
< jeremie at le-hen dot org >< ttz at chchile dot org >