A Native VLAN is the default VLAN that handles untagged traffic on trunk links in a network. Trunk links are simply connections between switches or between a switch and a router. These links let multiple VLANs share a single network connection by tagging Ethernet frames using the IEEE 802.1Q standard<\/a><\/strong>.\u00a0<\/p>\n\n\n\n The Native VLAN acts as a \u201chome\u201d for untagged frames\u2014data packets without a VLAN ID<\/a>. Instead of being discarded, these untagged frames are assigned to the Native VLAN, allowing them to be processed correctly.<\/p>\n\n\n\n The IEEE 802.1Q standard is the most common VLAN tagging protocol. It assigns VLAN IDs to Ethernet frames to help route them to their designated VLANs. However, frames from the Native VLAN remain untagged as they traverse trunk links. <\/p>\n\n\n\n Here\u2019s how it plays out on a trunk link:<\/p>\n\n\n\n To differentiate, think of tagged frames as packages with detailed labels and untagged frames as packages with generic labels assigned to a specific bin (Native VLAN). <\/p>\n\n\n\n When two switches on a trunk link have mismatched Native VLANs (for example, Switch A uses VLAN 1 and Switch B uses VLAN 10), it can cause major communication problems. This mismatch often results in dropped packets or packets being routed incorrectly, making it a common configuration mistake.<\/p>\n\n\n\n Setting up a Native VLAN involves configuring trunk ports on switches and assigning the desired VLAN as the Native VLAN. Below is a step-by-step approach using Cisco IOS syntax as an example: <\/p>\n\n\n\n Remember to maintain consistent Native VLAN IDs on both ends of a trunk link to avoid mismatches.\u00a0<\/p>\n <\/div><\/div><\/div><\/div>\n\n\n\n Native VLANs are often used in scenarios that require integration with untagged traffic or specialized network segments, such as:<\/p>\n\n\n\n By bridging newer and legacy technologies, Native VLANs allow businesses to optimize their network without significant hardware upgrades. <\/p>\n\n\n\n While Native VLAN simplifies untagged traffic handling, it introduces potential risks if improperly configured. <\/p>\n\n\n\nWhy Does Native VLAN Matter? <\/strong><\/h3>\n\n\n\n
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How Native VLAN Works <\/strong><\/h2>\n\n\n\n
Native VLAN and 802.1Q Tagging <\/strong><\/h3>\n\n\n\n
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Pitfall to Avoid <\/strong><\/h3>\n\n\n\n
Setting Up Native VLAN <\/strong><\/h2>\n\n\n\n
Step-by-Step Configuration <\/strong><\/h3>\n\n\n\n
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Switch# configure terminal <\/code><\/p>\n\n\n\nSwitch(config)# interface gigabitethernet 0\/1<\/code><\/p>\n\n\n\n\n
Switch(config-if)# switchport mode trunk<\/code><\/p>\n\n\n\n\n
Switch(config-if)# switchport trunk native vlan [VLAN_ID]<\/code><\/p>\n\n\n\n\n
Switch# show running-config | include interface<\/code><\/p>\n\n\n\n![](\"\/wp-content\/themes\/jumpcloud\/assets\/images\/gutenberg-blocks\/note-icon.png\"\/){kind=icon}
<\/p><\/div>Best Practices<\/strong><\/h3>\n\n\n\n
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Common Use Cases for Native VLAN <\/strong><\/h2>\n\n\n\n
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Security Considerations <\/strong><\/h2>\n\n\n\n
Key Vulnerabilities <\/strong><\/h3>\n\n\n\n