Bug report

Bug description:

>>> import ipaddress
>>> ip_address = ipaddress.ip_address("3fff::")
>>> ip_address.is_global
True

RFC 9637 registered the address block 3fff::/20 as NOT globally reachable in the IANA IPv6 Special-Purpose Address Registry, but the ipaddress module doesn't respect this.

CPython versions tested on:

3.11

Operating systems tested on:

macOS

Linked PRs

• gh-124217: Add RFC 9637 reserved IPv6 block 3fff::/20 #124240
• [3.13] gh-124217, ipaddress: Add RFC 9637 reserved IPv6 block 3fff::/20 (GH-124240) #124282
• [3.12] gh-124217, ipaddress: Add RFC 9637 reserved IPv6 block 3fff::/20 (GH-124240) #124283