# Why VLAN 1 Should Not Be Tagged in a Trunk

DevFeed: [Why VLAN 1 Should Not Be Tagged in a Trunk](<https://devfeed.tech/articles/tagged-vlan-1-in-a-trunk-is-a-really-bad-idea-11139.md>)

Original publisher: [Read original article](<https://blog.ipspace.net/2025/02/tagged-vlan-1/>)

Published: 2025-02-11T07:05:00Z

Content type: article

Language: en

Sources: [ipSpace.net blog](<https://devfeed.tech/sources/ipspace-net-blog.md>)

Topics: [Network](<https://devfeed.tech/topics/network.md>), [Ethernet](<https://devfeed.tech/topics/ethernet.md>), [DHCP](<https://devfeed.tech/topics/dhcp.md>), [Cisco](<https://devfeed.tech/topics/cisco.md>)

Tags: [bridging](<https://devfeed.tech/tags/bridging.md>), [cisco](<https://devfeed.tech/tags/cisco.md>), [dhcp](<https://devfeed.tech/tags/dhcp.md>), [ethernet](<https://devfeed.tech/tags/ethernet.md>), [lan](<https://devfeed.tech/tags/lan.md>), [netlab](<https://devfeed.tech/tags/netlab.md>), [network](<https://devfeed.tech/tags/network.md>), [security](<https://devfeed.tech/tags/security.md>)

## AI overview

The article examines conflicting interpretations of VLAN 1 in trunks by Cumulus NVUE and Arista EOS. It recommends avoiding VLAN 1 in VLAN trunks and using it as the native VLAN when necessary, while explaining the historical and operational reasons behind this behavior.

## Source excerpt

It all started with a netlab issue describing different interpretations of VLAN 1 in a trunk. While Cumulus NVUE (the way the netlab configuration template configures it) assumes that the VLAN 1 in a trunk is tagged, Arista EOS assumes it's the native VLAN. At that point, I should have said, "that's crazy, we shouldn't allow that" and enforce the "VLAN 1 has to be used as a native VLAN" rule. Alas, 20/20 hindsight never helped anyone. TL&DR: Do not use VLAN 1 in VLAN trunks; if you have to, use it as a native VLAN. Read more ...