Re: rfc 1812 third party address on traceroute

[Marc Storck <mstorck () voipgate com>]

I'm not saying anyone is wrong here. I merely want to point out eventual incompatabilities.

So please don't get me wrong.

Regards,

Marc

> On 1 juin 2016, at 23:46, William Herrin <bill () herrin us> wrote:
>
> 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?
>
> Hi Marc,
>
> 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.
>
> You've hit on a good reason to follow the RFC by default instead of
> doing what Randy wants. ;)
>
> -Bill
>
>
>
>
> -- 
> William Herrin ................ herrin () dirtside com  bill () herrin us
> Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>