Currently App Platform supports dual stack (IPv4 and IPv6) clients. This feature isn't able to be changed as of now. This poses an issue for servers requiring a single IP per user (such as rate-limiting, IP banning, etc), or even older analytics systems relying on a single IP from each user. This feature request is to be able to choose to listen to IPv4, IPv6, or dual-stack clients. Another option would be to add the Pseudo IPv4 header as CloudFlare also implements this: https://support.cloudflare.com/hc/en-us/articles/229666767-Understanding-and-configuring-Cloudflare-s-IPv6-support/#h_877db671-916a-4085-9676-8eb27eaa2a91.