Does a trunk port need a native VLAN?
A Trunk port (or “tagged port” in the non Cisco world) is a switch port which carries traffic for multiple VLANs. Access ports do not require a VLAN tag, since all incoming and outgoing frames belong to a single VLAN.
What does Switchport trunk native VLAN mean?
The switchport trunk native vlan command specifies the native (untagged) VLAN for a Layer 2 interface operating in trunk mode on a Cisco IOS device. This command only takes effect for interfaces that are operating in trunk mode.
What is no Switchport VLAN?
“no switchport access vlan” simply returns the port’s access vlan to the switch default. (usually “1”) “switchport trunk allowed vlan remove 2-4094” removes all vlans from the trunk port. If the switch default vlan is not “1”, the port will carry no traffic.
Does native VLAN need to be tagged?
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.
Is a native VLAN required?
In order to configure native VLAN, switch port trunk native VLAN command is used. Native VLANs are recognized if they are not tagged to any trunks. It is not necessary to have native VLAN on the trunk.
How do I tag a native VLAN?
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 across all trunk ports without regard to how the network should actually be configured.
What does no Switchport mean?
The no switchport command puts the interface in L3 mode (known as “routed port”) and makes it operate more like a router interface rather than a switch port. The ip address command assigns an IP address and network mask to the interface. Routed ports can be configured with a Layer 3 routing protocol.
Why do we use no Switchport command?
As mentioned above, the no switchport command is mainly used to configure routed ports. This helps Layer 3 switch reach the default router during the configuration of VLAN. In terms of the configuration of the routed port, you can get into interface configuration mode of a switch and issue the command no switchport.
Why won’t VLAN 600 tags work on this trunk link?
1) it sends any frames for vlan 600 on that trunk link with no tag. If the switch on the other end is expecting tags for that frame it isn’t going to work. 2) any frames received on that trunk link with no tag are assumed to be in vlan 600.
Why are any frames in the native VLAN untagged?
Any frames in the native vlan are untagged on trunk links. I agree, it is unusual ie. if you go to the trouble of setting the native vlan you usually use a vlan with no end user ports in it. 06-05-2015 01:52 PM
What is VLAN ID 0 on a vSwitch equivalent to?
From what I understand, VLAN ID 0 on a vswitch is equivalent to an untagged access port. On the switch side, is setting switchport trunk native vlan 555 on the interface applying a tag to 555 traffic? Or does this setting explicitly pass the frame as untagged? It seems odd to me that the native vlan would be associated with data traffic.
What is a trunk port in a VLAN?
A trunk port is a member of all VLANs by default, including extended-range VLANs, but membership can be limited by configuring the allowed-VLAN list. You can also modify the pruning-eligible list to block flooded traffic to VLANs on trunk ports that are included in the list.