| VLAN Commands
Configuring VLAN Interfaces
All ports are assigned to VLAN 1 by default.
The default frame type is untagged.
Interface Configuration (Ethernet, Port Channel)
If a port or trunk has switchport mode set to access, then only one VLAN can be
added with this command. If a VLAN list is specified, only the last VLAN in the
list will be added to the interface.
A port, or a trunk with switchport mode set to hybrid, must be assigned to at
least one VLAN as untagged.
If a trunk has switchport mode set to trunk (i.e., 1Q Trunk), then you can only
assign an interface to VLAN groups as a tagged member.
Frames are always tagged within the switch. The tagged/untagged parameter
used when adding a VLAN to an interface tells the switch whether to keep or
remove the tag from a frame on egress.
If none of the intermediate network devices nor the host at the other end of the
connection supports VLANs, the interface should be added to these VLANs as
an untagged member. Otherwise, it is only necessary to add at most one VLAN
as untagged, and this should correspond to the native VLAN for the interface.
If a VLAN on the forbidden list for an interface is manually added to that
interface, the VLAN is automatically removed from the forbidden list for that
The following example shows how to add VLANs 1, 2, 5 and 6 to the allowed list as
tagged VLANs for port 1:
Console(config)#interface ethernet 1/1
Console(config-if)#switchport allowed vlan add 1,2,5,6 tagged
This command enables ingress filtering for an interface. Use the no form to restore
[no] switchport ingress-filtering
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