[189538] in North American Network Operators' Group
Re: rfc 1812 third party address on traceroute
daemon@ATHENA.MIT.EDU (Octavio Alvarez)
Wed Jun 1 17:03:47 2016
X-Original-To: nanog@nanog.org
To: William Herrin <bill@herrin.us>
From: Octavio Alvarez <octalnanog@alvarezp.org>
Date: Wed, 1 Jun 2016 14:03:41 -0700
In-Reply-To: <CAP-guGUsvq55npDEFdCdZheszOBR2Vr+ZHGUnHrzcgUDbNaCRQ@mail.gmail.com>
Cc: North American Network Operators' Group <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
On 05/31/2016 11:22 AM, William Herrin wrote:
>> I'm not sure if you mean that, if sent through C it should have the
>> source addres of A, or that it should actually be sent through A
>> regardless of the routing table (which sounds better to me).
>
> That doesn't make sense. There may be multiple next hops out A. If the
> next hop in the FIB is out C, how would the router pick the next hop
> to send to out A?
Back to the physical address that sent the TTL-offending packet.
> Anyway, Randy's comment was about source address selection, not
> routing. With the packet coming from S into interface A, he'd prefer
> that the ICMP error message be sourced from the IP address assigned to
> A, not the IP address assigned to C or R.
Thanks.
