In one embodiment, a list of source identifiers is maintained at a virtual switch. These source identifiers are allowed to send packets through the virtual switch to ports in a private virtual local area network (PVLAN). When a packet is received at the virtual switch from a particular source destined for a particular port in the PVLAN, the virtual switch determines whether a particular identifier associated with the particular source matches one of the source identifiers in the list. If that particular source identifier is not on the list, the packet is prevented from being forwarded to the particular port in the PVLAN.