ipaddress.IPv4Address and ipaddress.IPv6Address provide a is_private function that indicates if the address (or network) is part of a "private" IP range, as designated by the IANA special-use registry. The current documentation is as follows: > is_private > True if the address is allocated for private networks. See iana-ipv4-special-registry (for IPv4) or iana-ipv6-special-registry (for IPv6). However, IPv4-mapped IPv6 addresses are currently being reported as "private" by this function (see https://github.com/python/cpython/commit/22c31764262b02338265a059c738b8d24fd9a0e4#diff-0fc57874e463b95dbdfe6f80ae918ea1R1869). I consider this a bug or at least counter-intuitive, because e.g. ::ffff:8.8.8.8 is most definitely NOT a private IP address, and yet the ipaddress.is_private function reports True. The IANA special-use registry does not contain any references to "being private" for the ::ffff region. It just designates it to be used for IPv4-mapped address.
Questionable as to if this counts as a bug or not, but I agree it is counter-intuitive given the purpose of actually checking the .is_private property of an address. So updating the behavior makes sense, but I'll be conservative w.r.t. behavior changes and not apply this to a 3.9 or earlier.
