On 10/25/2014 1:00 AM, pepe wrote: > I know it's usually done with /64, but my ISP just said: your block is > 2001:14b8:1801::/48 and > defaultrouter should be ::1. So I can't really change that. They meant your allocation is 2001:14b8:1801::/48. You can subnet that however you like. Subnetting at /64 is BCP for a lot of reasons.