For threat remediation in a third-party network, the RADIUS protocol is necessary to communicate with the RADIUS server for details about infected hosts. CoA enables security measures to be enforced based on endpoint information provided by the RADIUS server. Details on this setup can be found in Juniper RADIUS and AAA Documentation.
When deploying threat remediation to endpoints connected through third-party devices, such as switches, the following conditions must be met for proper integration and functioning:
Explanation of Answer A (Support for AAA/RADIUS and Dynamic Authorization Extensions):
Third-party switches must support AAA (Authentication, Authorization, and Accounting) and RADIUS with Dynamic Authorization Extensions. These extensions allow dynamic updates to be made to a session's authorization parameters, which are essential for enforcing access control based on threat detection.
The connector uses an API to gather MAC address information from the RADIUS server. This MAC address data is necessary to identify and take action on infected hosts or endpoints.
The connector queries the RADIUS server for infected host details and triggers a Change of Authorization (CoA) for the infected host. The CoA allows the connector to dynamically alter the host's access permissions or isolate the infected host based on its threat status.

Exception traffic, including management and control plane traffic, is handled by examining host- inbound traffic configurations at the ingress interface and zone. It ensures traffic reaches necessary services like SSH and IKE securely.
SRX Series devices handle exception traffic (such as management traffic like SSH, Telnet, DNS queries, etc.) differently than regular transit traffic. Exception traffic is examined based on host- inbound traffic for the ingress interface and zone. If traffic is destined for the device itself (e.g., management traffic or routing protocol messages), it must be allowed as host-inbound traffic on both the ingress interface and zone.

Policy Enforcer interacts with other network elements like EX switches to enforce blocking of infected hosts based on threat intelligence from ATP Cloud and other sources.
In a Juniper automated threat mitigation setup involving Security Director, Policy Enforcer, Juniper ATP Cloud, SRX Series, and EX Series switches, the Policy Enforcer is the component responsible for blocking infected hosts.