The 802.1q VLAN protocol allows remote attackers to bypass network segmentation and spoof VLAN traffic via a message with two 802.1q tags, which causes the second tag to be redirected from a downstream switch after the first tag has been stripped, as demonstrated by Yersinia, aka "double-tagging VLAN jumping attack."

The PVLAN protocol allows remote attackers to bypass network segmentation and spoof PVLAN traffic via a PVLAN message with a target MAC address that is set to a gateway router, which causes the packet to be sent to the router, where the source MAC is modified, aka "Modification of the MAC spoofing PVLAN jumping attack," as demonstrated by pvlan.c.