Which vlans are allowed across trunk

The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Which VLANs are allowed on this trunk? Ask Question. Asked 7 years, 7 months ago. Active 5 years, 2 months ago.

Viewed 24k times. Improve this question. Axel Kennedal Axel Kennedal 4 4 gold badges 9 9 silver badges 16 16 bronze badges. Add a comment. Active Oldest Votes. If you decide to configure both ends of a trunk link as a fixed trunk switchport mode trunk , you can disable DTP completely so that these frames are not exchanged.

To do this, add the switchport nonegotiate command to the interface configuration. Be aware that after DTP frames are disabled, no future negotiation is possible until this configuration is reversed.

As an example of trunk configuration, consider two switches, Switch-D and Switch-A, which are distribution-layer and access-layer switches , respectively. The trunk link should use First, configure Switch-D to actively negotiate a trunk with the far-end switch. You could use the following configuration commands on Switch-D:. At this point, you assume that Switch-A is configured correctly, too. Now, you should try to verify that the trunk is working as expected.

On Switch-D, you can view the trunk status with the following command:. To your surprise, the trunk's status is not-trunking. Next, you should verify that the physical link is up:. Pearson Education, Inc. This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site.

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How to define the VLANs allowed on a trunk link. Labels: Other Switching. Resolution When a trunk link is established, all of the configured VLANs are allowed to send and receive traffic across the link.

For Integrated Cisco IOS Software based switches perform these steps: To restrict the traffic that a trunk carries, issue the switchport trunk vlan-list interface configuration command. This removes specific VLANs from the allowed list. This example shows how to remove VLANs 5 through 10 and Even if you specify a VLAN range, it is ignored. Tags: authentication. Switchport trunk allowed vlan all What is the advantage of allowing certain vlans vs allowing all?