What ports need to be open in the firewall to resolve connection issues with auth.cpanel.net?
Port 2089 outbound is the official license port. If this port fails to connect, the software will also try connecting outbound with the following ports:
- 23, 25, 80, 110, 143, 993, 995, 2089
Port 2083 inbound is used to deploy the license file, so it should be open. DNSOnly servers do not listen on port 2083, so port 2087 would need to be open inbound on those servers.
You must configure your system to permit outbound TCP connections from source ports
1020 to destination port
2089. This will allow the server to contact the cPanel, L.L.C. license servers. Servers should have port 53 open outbound for TCP and UDP traffic in order to resolve the DNS for the licensing servers.
See also this page for more information: How to Configure Your Firewall for cPanel & WHM Services.