Weird behavior with ULA addressing (fc00::/7)

[someara]

Specifically on OSX and Windows 11

[glimberg]

https://datatracker.ietf.org/doc/draft-ietf-v6ops-ula/

[laduke]

such as?

[glimberg]

@laduke This came up in a call with IPArchitects last week. Waiting for more info from them

[aadnehovda]

I'll just add this here since I searched the issues for any reference to fc00 and this came up. The whole fc00::/7 block is assigned for ULA, however fc00::/8 is reserved for "future use", in anticipation of a global assignment system of local addresses (https://datatracker.ietf.org/doc/html/rfc4193#section-3.2, second paragraph).

So only fd00::/8 addresses should be used for now. 6PLANE addresses assigned by my.zerotier.com are from the reserved block. Of course this probably does not matter much in practice, just something I noticed today.