Re: [Int-area] Existing use of IP protocol 114 (any 0-hop protocol)

[Fernando Gont <[e-mail]>]

On 19/9/19 18:06, Eric Vyncke (evyncke) wrote:
> The authors of https://tools.ietf.org/id/draft-zhu-intarea-gma-03.txt
> would like to use IP protocol 114 as it is described as “Any 0-hop
> protocol” on the IANA page[1]. Alas, on the IANA page, there is no
> reference to this “Any 0-hop protocol”.
> 
>  
> 
> Obviously, we all understand that this must be a protocol using hop
> limit = 0 (or TTL=0 for the legacy protocol).

Just a (mostly side) comment:

The hop limit thins is tricky:
Some 0-hop (non-routable?) protocols actually use a high (e.g. 255) TTL,
such that it can be enforced ("''''security''''-wise") that the parties
are actually on the same network segment.

Others (was it mld?) employ small hop limit values, such that you can
control how far packets can leak out.

So the protocol might actually use small or large hop limit, depending
on whether you want to make sure that packets cannot be injected, or
that packets cannot leak out.

Thanks!

Cheers,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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