The key a client IP is rate-limited under: an IPv4 address as is (also when
written as ::ffff:192.0.2.1, as dual-stack sockets report IPv4 clients),
an IPv6 address by its /64 prefix, in one canonical form whatever the
notation (compressed, zone id, brackets, port). One IPv6 host usually gets a
whole /64, so keying on the full address let it take a fresh budget for
every address it rotated to. Anything that is not an IP is returned as is.
The key a client IP is rate-limited under: an IPv4 address as is (also when written as
::ffff:192.0.2.1, as dual-stack sockets report IPv4 clients), an IPv6 address by its /64 prefix, in one canonical form whatever the notation (compressed, zone id, brackets, port). One IPv6 host usually gets a whole /64, so keying on the full address let it take a fresh budget for every address it rotated to. Anything that is not an IP is returned as is.