fc00::/7 are ULA (basically what RFC1918 was for IPv4) not entirely true, fc00::/8 is part of ULA, but it is not yet defined. Use fd00::/8 instead.
2001:db8::/32 is for documentation purposes
IMO they shouldn’t have allowed ULA as part of the standard. There’s no good reason for it.
I use ULA prefixes to ensure the management interfaces of my devices don’t leak via public routes.
It’s one of the unique parts of the standard IPv6 stack not back ported to IPv4, that an interface on any host can be configured with multiple addresses. It permits functional isolation with the default routing logic.
IPv6 is far from perfect, but the majority of the arguments I’ve seen against deploying it are a mixture of laziness, wilful ignorance, and terminal incuriosity.
Yeah there is: not breaking all your internal traffic when the wan link goes down and you lose your prefix.
You’re not supposed to use fc00::/8, so it’s just the fd00::/8 half that’s the new ULA.
Didn’t know that, thanks. Luckily, I’ve only ever used fd00::/8
Source btw: https://en.m.wikipedia.org/wiki/Unique_local_address#Definition