[xyzzy123]

It would also allow a pretty trivial bypass using ipv6. A sizeable % of ip-based rate limits are breakable if you can use v6; iirc for a long time google web properties had bypassable rate limits if you knew about this.

[j16sdiz]

Have you tried it?

In my experience, gmail is lot stricter on ipv6. They have been requiring SPF and rDNS on IPv6 before this announcement.

[xyzzy123]

Yep I am talking about maybe a decade ago; google have fixed the issues I knew about but lots of systems still only limit v4 effectively.