What cPanel IPs do my cPanel servers need to connect to?
Your server will need to connect to the following cPanel subdomains and ports for installations, updates, and licensing.
To see the IPs that these subdomains are associated with, you can run the following commands.
dig +short auth.cpanel.net
dig +short rdate.cpanel.net
dig +short httpupdate.cpanel.net
dig +short securedownloads.cpanel.net