From mboxrd@z Thu Jan  1 00:00:00 1970
From: Grant Taylor <gtaylor@tnetconsulting.net>
Date: Sun, 17 Mar 2019 18:38:39 +0000
Subject: Re: Failover route
Message-Id: <e1f374bb-ff8c-7164-aa7a-60c12debd39b@spamtrap.tnetconsulting.net>
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List-Id: <lartc.vger.kernel.org>
References: <43b5d3a3aa714ace92882f9fe9c594ce@ODC-EXC-MBX-C03.harriscomputer.com>
In-Reply-To: <43b5d3a3aa714ace92882f9fe9c594ce@ODC-EXC-MBX-C03.harriscomputer.com>
To: lartc@vger.kernel.org

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On 3/16/19 12:04 PM, Erik Auerswald wrote:
> Hi,

Hi,

> Yeah, one needs to send a packet destined to the same machine out an=20
> interface. That might need some trickery.

The more that I think about it, the more that I think:

  =C2=B7 BFD-EM style to-be-routed packet might work better than ICMP.
  =C2=B7 link-net IPs shouldn't be a problem.

> I remember some related trickery from a Project Zero blog post:=20
> googleprojectzero.blogspot.de/2015/12/fireeye-exploitation-project-zero=
s.html

Either I'm not understanding what you're referring to.  Or I don't see=20
how essentially sniffing a (mirror / SPAN) port differs from what I said =

previously about sniffing traffic.

Or are you talking about applying sniffing to the BFD-EM frame?

> A BFD daemon using RAW sockets (neither UDP nor TCP) might not need=20
> something like the above, similar to ping -I <Iface> -r <TargetIP>.

I'm really starting to question if I'm / we're not over complicating this=
=2E

I can't think of a reason why BFD-EM to from & to the local link-net IP=20
via the far end router's MAC address won't work.

The link-net IPs should only be used for things on the link.  So I don't =

see any disadvantage of said IPs not being reachable if the link is down =

/ down.  Arguably, that's a state that BFD-EM should account for.  The=20
reason for using BFD-EM would want to know about such a down / down state=
=2E



--=20
Grant. . . .
unix || die


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