[189543] in North American Network Operators' Group
Re: rfc 1812 third party address on traceroute
daemon@ATHENA.MIT.EDU (Marc Storck)
Wed Jun 1 17:50:38 2016
X-Original-To: nanog@nanog.org
From: Marc Storck <mstorck@voipgate.com>
To: William Herrin <bill@herrin.us>
Date: Wed, 1 Jun 2016 21:50:28 +0000
In-Reply-To: <CAP-guGXDpODk+pofWiRqUciE8fQk61+p9O3NLod96by1izX3Kw@mail.gmail.com>
Cc: North American Network Operators' Group <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
I'm not saying anyone is wrong here. I merely want to point out eventual in=
compatabilities.
So please don't get me wrong.
Regards,
Marc
> On 1 juin 2016, at 23:46, William Herrin <bill@herrin.us> wrote:
>=20
> On Wed, Jun 1, 2016 at 3:16 PM, Marc Storck <mstorck@voipgate.com> wrote:
>>> .-----------------.
>>> | |
>>> | B |--------- D
>>> S ---------| A R |
>>> | C |--------- (toward S)
>>> | |
>>> `-----------------'
>> With BCP38 in mind, could there be situations
>> where Router R is not allowed to source packets
>> with address A out of interface C?
>=20
> Hi Marc,
>=20
> I think you're right. Address A in a /30 from ISP A. ISP C accepts
> source addresses from your /24 but not the A /30. So if the router
> does not follow the RFC (sends an ICMP packet out C with a source
> address from A), typical asynchronous routing can result in
> black-holding the ICMP error message.
>=20
> You've hit on a good reason to follow the RFC by default instead of
> doing what Randy wants. ;)
>=20
> -Bill
>=20
>=20
>=20
>=20
> --=20
> William Herrin ................ herrin@dirtside.com bill@herrin.us
> Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>
