Firewall rules must be configured on the Tanium Zone Server for Client-to-Zone Server communications.

In customer environments using the Tanium Zone Server, a Tanium Client may be configured to point to a Zone Server instead of a Tanium Server. The communication requirements for these Clients are identical to the Server-to-Client requirements. https://docs.tanium.com/platform_install/platform_install/reference_network_ports.html