Port Forwarding - IP Range in use by Plex instead of Any

I have been using Plex for many years, but as I am becoming more concerned with network security it would be preferable for the port forward to allow only for an IP address or a range of IP addresses to connect to my public IP and selected port.

I have reviewed the documentation provided by Plex but I have not found any requisite whitelist or specific IP addresses that Plex will use to allow Plex.tv to function.

Is there documentation that someone is aware of?

Unless a client is using a Plex relay, then the client will only use Plex.tv to find the address of your server and then connect directly.

There are a couple of IPs which are used by Plex to test your remote access status. These are updated at https://s3-eu-west-1.amazonaws.com/plex-sidekiq-servers-list/sidekiqIPs.txt and should be allowed through the firewall.

You can then restrict other IPs to only the remote client IPs you wish to let access the server.