Question: Why Would You Change The Native VLAN?

What is the difference between native VLAN and default VLAN?

Native VLAN concept exists in case of encapsulation type 802.1Q (802.1Q supports untagged traffic while ISL does not support untagged traffic).

In terms of encapsulation, Default VLAN is seen to support both DOT1Q and ISL encapsulations.

On the contrary, Native VLAN only exists in DOT1Q encapsulation type..

Does native VLAN need to be allowed on trunk?

There is a misconception that you must have a native VLAN on a trunk. The link-local protocols that send frames without tags will still work. They really are not part of a VLAN, native or otherwise. The NATIVE VLAN should NOT be included on the “switch allowed vlan” list.

How do you do VLAN hopping?

There are two primary methods of VLAN hopping: switch spoofing and double tagging. Both attack vectors can be mitigated with proper switch port configuration….MitigationSimply do not put any hosts on VLAN 1 (The default VLAN). … Change the native VLAN on all trunk ports to an unused VLAN ID.More items…

How do I disable native VLAN?

To configure the native VLAN ID for the virtual Ethernet interface, use the switchport trunk native vlan command. To remove the native VLAN ID from the virtual Ethernet interface, use the no form of this command.

What does untagged VLAN mean?

untagged – means that if there is packets on this port that have no vlan id set will have their vlan id tag set to this vlan by the switch. Packets that do have a vlan tag with this vlan id will bei ignored. This means that the client must not tag packets for this vlan.

Why you should not use VLAN 1?

This old discussion from Cisco forum states it very clearly: You should never use the default VLAN either because VLAN hopping is much more easily accomplished from the default VLAN. … An attacker being located on a non-native VLAN manages to turn a switch access port into a trunk one.

What is the native VLAN?

native vlan means that device will never put/insert tag (VLAN ID, in you case “VLAN ID:2”) on Ethernet frame when it leaves port and also when Ethernet frame without tag go into that port device will put/insert tag defined by native vlan ( in you case VLAN ID:2).

How do I find my native VLAN?

Use the show interfaces trunk command to check whether the local and peer native VLANs match. If the native VLAN does not match on both sides, VLAN leaking occurs. Use the show interfaces trunk command to check whether a trunk has been established between switches.

How do I remove a VLAN from my trunk?

Removing VLANs from the trunk of a virtual port channelLog in to Cisco Nexus series switch.To run the configuration, type: Switch-A# config terminal.Type: Switch-A(config)# interface port-channel port_channel_number.To remove the VLAN ID, type: Switch-A(config-if)# switchport trunk allowed vlan remove VLAN_IDs.

Why do we need 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.