Abstract: Provided are techniques for to enable a virtual input/output server (VIOS) to establish cryptographically secure signals with target LPARs to detect an imposter or spoofing LPAR. The secure signal, or “heartbeat,” may be configured as an Internet Key Exchange/Internet Protocol Security (IKE/IPSec) encapsulated packet (ESP) connection or tunnel. Within the tunnel, the VIOS pings each target LPAR and, if a heartbeat is interrupted, the VIOS makes a determination as to whether the tunnel is broken, the corresponding LPAR is down or a media access control (MAC) spoofing attach is occurring. The determination is made by sending a heartbeat that is designed to fail unless the heartbeat is received by a spoofing device.