Promiscuous ports
A promiscuous port is a switch port that is connected to a router, firewall, Level 3 switch, or other Common Gateway device. Promiscuous ports can communicate with all types of ports within a PVLAN (private VLAN) domain, including community ports and isolated ports.
Promiscuous ports must be members of the primary VLAN.
By default, every port in the primary VLAN is configured as a promiscuous port.