Traefik Mesh ACL mode transition for internal service isolation

Traefik Mesh implements a permissive default posture where services are reachable by any other meshed workload upon joining the mesh. To prevent accidental internal exposure, the mesh provides an ACL mode based on the Service Mesh Interface (SMI) TrafficTarget specification.

When transitioning from a permissive setup to a restrictive one, the primary goal is to ensure a deny-by-default state where only explicitly defined source-to-destination paths are permitted. However, there is uncertainty regarding how these ACLs are enforced when workloads utilize headless services or attempt direct pod-to-pod communication that may bypass the node-level proxy.

Given the current architecture of Traefik Mesh's transparent proxying, what is the expected behavior for traffic targeting headless services when ACL mode is enabled? Does the mesh maintain enforcement for direct pod IP communication, or does this create a security gap in the deny-by-default assumption?