What does the native VLAN do?
Native VLAN: The native VLAN is the one into which untagged traffic will be put when it’s received on a trunk port. This makes it possible for your VLAN to support legacy devices or devices that don’t tag their traffic like some wireless access points and simply network attached devices.
Should I tag native VLAN?
In Cisco LAN switch environments the native VLAN is typically untagged on 802.1Q trunk ports. This can lead to a security vulnerability in your network environment. It is a best practice to explicitly tag the native VLAN in order to prevent against crafted 802.1Q double-tagged packets from traversing VLANs.
Which VLAN ID is the native VLAN?
VLAN 1 is the default VLAN on Cisco switch ports, including the default native VLAN. It is special as it is the default. Also, there are also some types of layer-2 traffic that will always use VLAN (at least on a Cisco switch), such as CDP and LLDP.
How is a tagged VLAN different from a native VLAN?
If a frame on the native VLAN leaves a trunk (tagged) port, the switch strips the VLAN tag out. In short, the native VLAN is a way of carrying untagged traffic across one or more switches. Consider this Example. The ports that the hosts connect to are trunk ports, with native VLAN 15 configured.
Where is the native VLAN on a Cisco switch?
In Cisco LAN switch environments the native VLAN is typically untagged on 802.1Q trunk ports. This can lead to a security vulnerability in your network environment.
What does the native VLAN Dot1q tag command do?
Keep in mind that the vlan dot1q tag native command applies only to tagging frames on trunk ports. It has no effect on access ports – these ports will continue operating in untagged mode.
Is it bad practice to tag all VLANs?
The other technique is to not use the native VLAN on trunk ports on any access port where an attacker may be located. This can be done by using the “switchport trunk native vlan [vlanid]” on the Ethernet switch’s trunk port interface and then removing that VLAN from the trunk port. It is also a bad practice to simply tag all VLANs