Don’t forget, you can also use SRV records to point a domain to another target, where you can also omit the port number. So connecting to server.org say, can point to mc.server.org:25565 under the hood.
This prolly isn’t what hypixel are doing as everything’s likely on the same network and their router/firewall is just forwarding traffic onto different machines, but SRV is one way to redirect a minecraft connection (and you could combine the technique with subdomains).
Don’t forget, you can also use SRV records to point a domain to another target, where you can also omit the port number. So connecting to server.org say, can point to mc.server.org:25565 under the hood.
This prolly isn’t what hypixel are doing as everything’s likely on the same network and their router/firewall is just forwarding traffic onto different machines, but SRV is one way to redirect a minecraft connection (and you could combine the technique with subdomains).