A method and associated systems for enhanced isolation and security hardening among multi-tenant workloads. An agent running on a processor of a networked computer system on which multicast and broadcast communications have been disabled captures an address-resolution query message from a querying tenant, converts the query message to a unicast message, and forwards the converted unicast query message to a switch. The switch forwards the converted unicast message to a redirection device and in response receives an address-resolution response message only after the redirection device verifies that the query and response messages comply with security policies. The switch forwards the address-resolution response to the querying tenant in conformance with security policies.