Ensure that the firewall rules allow outbound connections to the following addresses as you might not be able to download System Update, PRU, Patches and ZENworks NEWS.
Primary Server performs the ZENworks System Update Entitlement registration or activation over HTTPS (port 443) using the secure-www.novell.com website. This rule can be turned off after successfully completing the entitlement activation.
ZENworks System Update, PRU (Checks and Downloads) and ZENworks NEWS are shared over HTTPS (port 443) using the nu.novell.com website.
For more information on list of Patch provider websites that requires outbound connectivity to download patches, see Patches are unavailable because of connectivity or firewall issues.
For more information of TCP and UDP ports used by ZENworks Primary Servers, see ZENworks 2020 TCP and UDP Ports.