> I wonder how many customers can realistically hide behind a single IPv4 (CGNAT), given that there are 65535 TCP/UDP ports.
In theory, one IPv4 address can maintain 65535 connections with every HTTPS server (TCP port 443) on the Internet simultaneously. The main cause of port depletion would be when lots of users connect to the same server.
A reasonable number is 1000 users with 64 ports each, but you could probably squeeze in another 10X.
Some servers can work reliably with only IPv6, for instance, until you need to contact IPv4-only servers.
I would like my mail server to be IPv6-only, but that's not currently possible, for instance.
I wonder how many customers can realistically hide behind a single IPv4 (CGNAT), given that there are 65535 TCP/UDP ports.