As suggested in a previous forum post, I'm putting in a feature request for improved IPv6 support. PMS supports "List of networks that are allowed without auth" for IPv4 (this works), but it doesn't work for IPv6.
For more information, please see my other thread: https://forums.plex.tv/topic/124059-ipv6-no-auth-acl-does-not-seem-to-work/
If you have any questions, please let me know by replying to this thread.