Assign entire subnets of public IP4/IP6 to a single app?

[ignoramous]

Vend those addresses out to downstream clients, as a way to ID traffic coming from them, and apply whatever policies as set by them. The appeal is, such a mechanism would be protocol agnostic… I realise that today fly only supports TCP (over 4 and 6) and UDP (over 4) transports.

IPv6 UDP?

The usecase I have for IPv6 UDP (not solvable with IPv4) is transparently proxying TCP/UDP connections. For ex, our DNS resolver always answers with our app’s fly IPs for all DNS requests from our clients. That is, say example.com from client-A gets 2a09:8080:1::abcd, while example.com from client-B gets 2a09:8080:1::1234 (assuming both of those IPv6 are assigned to our fly app). Then, when a UDP/TCP request from client-A hits 2a09:8280:1::abcd, the fly app (reading from the mapping set by th…