On Wed, Jan 15, 2014 at 12:54 PM, Niels Bakker <niels=nanog@bakker.net> wrote:
* nanog@shankland.org (Jim Shankland) [Wed 15 Jan 2014, 18:04 CET]:
So ... RFC1918 addresses for the IXP fabric, then?
(Half kidding, but still ....)
They need to be globally unique.
Hi Niels, Actually, they don't. To meet the basic definition of working, they just have to be able to originate ICMP destination unreachable packets with a reasonable expectation that the recipient will receive those packets. Global uniqueness is not required for that. However, RFC1918 addresses don't meet the requirement for a different reason: they're routinely dropped at AS borders, thus don't have an expectation of reaching the external destination. Of course working, monitorable and testable are three different things. If my NMS can't reach the IXP's addresses, my view of the IXP is impaired. And "the Internet is broken" is not a trouble report that leads to a successful outcome with customer support... it helps to be able to pin things down with some specificity. Regards, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004