On 25/04/2017 10:44, Michael Fincham wrote:
On Tue, 25 Apr 2017 09:26:45 +1200, Matthew Poole wrote:
A /64 is definitely recommended as the maximum prefix length for any purpose, even point-to-point links.
I'm with you on finding this really disconcerting, but that paper lays out why you shouldn't go longer than /64 for your prefixes.
I would suggest for point-to-point links that folks register them in their IPAM as a /64, but configure them on the equipment as a /127.
As far as I can tell, essentially all equipment supports this configuration, but you cut down your exposure to various bugs and bad behaviours that have cropped up in the past (e.g. ping-pong and friends).
Also stops people from being tempted to slip extra hosts in to what should be a point-to-point link.
That's true, but in principle you can do whatever the heck you like on a router-to-router link. Any equipment that actually limits you to a /64 is somewhat broken. For background: https://tools.ietf.org/html/rfc7421 Brian