Networking security policies determine how the adapter filters inbound and outbound frames.

Layer 2 is the Data Link Layer. The three elements of the security policy are promiscuous mode, MAC address changes, and forged transmits.

In nonpromiscuous mode, a guest adapter listens only to traffic forwarded to own MAC address. In promiscuous mode, it can listen to all the frames. By default, guest adapters are set to nonpromiscuous mode.