Untagged ingress packets are destined to the native VLAN. An interface can be configured in one of 2 native modes - native untagged or native tagged.
A native untagged port accepts any untagged or tagged (with native VLAN ID) traffic on ingress.
Packets that egress on a native untagged port in the native VLAN will not have an 802.1Q header.
A native tagged port accepts only tagged traffic (with native VLAN ID) on ingress.
Any untagged packet ingress on a native tagged port is always dropped.
Packets that egress on a native tagged port in the native VLAN will always have an 802.1Q header.
(switch#) Configure a VLAN as native.
enable
configure terminal
vlan 3
exit
interface ethernet 1/1
switchport mode hybrid
switchport access vlan 3
(switch#)
show interface switchport