I think you mean /127 since a /128 would not support 2 points on the point to point.
Owen > On Jan 17, 2017, at 13:07 , Matthew Huff <mh...@ox.com> wrote: > > The reason for allocating a /64 for a point to point link is due to various > denial of service attack vectors. Just do it. The numbers in IPv6 are > staggering. The generally accepted best practice is to allocate a /64 and use > a /128 within that /64 for point to point links. > > ---- > Matthew Huff | 1 Manhattanville Rd > Director of Operations | Purchase, NY 10577 > OTA Management LLC | Phone: 914-460-4039 > aim: matthewbhuff | Fax: 914-694-5669 > > >> -----Original Message----- >> From: NANOG [mailto:nanog-boun...@nanog.org] On Behalf Of William >> Herrin >> Sent: Tuesday, January 17, 2017 4:02 PM >> To: Michael Still <stillwa...@gmail.com> >> Cc: nanog@nanog.org >> Subject: Re: Questions on IPv6 deployment >> >> On Tue, Jan 17, 2017 at 12:48 PM, Michael Still <stillwa...@gmail.com> >> wrote: >>> http://nabcop.org/index.php/IPv6_Subnetting >> >> That's overall good advice. I quibble with a couple of points: >> >> 1. If you plan to use a /126 on a point to point and can't imagine how >> you would use a /64 on that point to point, don't allocate a /64. Odds >> are that by the time you can imagine some way to use a /64 there, the >> details will require you to assign a new block anyway. >> >> Why be concerned about resource consumption? Because it's a good >> habit. Don't overdo it, IPv6 is not resource constrained the way IPv4 >> is, but shrewd use of available resources is a good habit even when >> resources are plentiful. >> >> 2. Make all your point to points /124. That will work for all your >> point to points. Serial or ethernet. Even the ethernets which have two >> high-availability routers on both ends along with the failover address >> needing a total of 6 IPs plus 1 for your troubleshooting laptop. >> Configuring /124 every time allows you to standardize your >> configuration, the same way /64 standardizes the netmask on a LAN >> deployment. >> >> >> >> One additional point not brought up: >> >> Minimum assignment to a customer: /60. Never ever /64 or /128. How >> much more than a /60 you choose as your minimum is up to you. Common >> choices are /56 and /48. But never, ever less than a /60. Your >> customer will want to deploy a /64 to each LAN. And there are so many >> cases where he'll want to deploy more than one LAN. >> >> I've noticed a lot of hosting providers getting this wrong. Some of >> your customers do create VPNs on their VPC you know. >> >> Regards, >> Bill Herrin >> >> >> -- >> William Herrin ................ her...@dirtside.com b...@herrin.us >> Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>