[192927] in North American Network Operators' Group
Re: Forwarding issues related to MACs starting with a 4 or a 6 (Was:
daemon@ATHENA.MIT.EDU (Saku Ytti)
Fri Dec 2 18:17:53 2016
X-Original-To: nanog@nanog.org
In-Reply-To: <CAG4d1reQO7R7dX4dDQMSiq6rU7EWS23FdVxmCRZJYwSZBK3KLw@mail.gmail.com>
From: Saku Ytti <saku@ytti.fi>
Date: Sat, 3 Dec 2016 01:17:48 +0200
To: Alia Atlas <akatlas@gmail.com>
Cc: nanog list <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
On 2 December 2016 at 18:16, Alia Atlas <akatlas@gmail.com> wrote:
> This sounds related to the well-known (at least 10+ years) issues around
> guessing the
> type of IP packet by looking at the first nibble of the encapsulated packet.
> Take a quick look at RFC 7325, section 2.4.5.1 bullet 6.
> This is what using the pseudo-wire code-word is meant to protect against.
>
> I don't know if that's an option for networks using this.
Some devices by default look inside pseudowires to find IP inside
them, in this case even control-word won't help, you'll need to also
disable looking inside pseudowire.
--
++ytti
