OSI LAYER 2 // Data Link Layer

VLAN Hopping

VLAN hopping abuses trunk/access-port configuration or negotiation behavior to reach traffic in another VLAN.

PREMIUM RESOURCE

01 // HOW IT WORKS

Mechanism

Misconfigured trunks, native VLAN behavior, or automatic negotiation can create unintended VLAN reachability.

02 // DETECTION

Indicators to watch

Unexpected trunk formation, access ports carrying tagged traffic, native VLAN anomalies, and cross-VLAN traffic where it should not exist.

03 // ATTACK FLOW

Concept diagram

01Access / trunk port↓

02Unexpected VLAN tagging↓

03Cross-VLAN path↓

04Segmentation weakened↓

05Explicit trunk configuration

04 // PREVENTION

Defensive controls

Disable unnecessary trunk negotiation, explicitly configure trunks, avoid native VLAN exposure, use VLAN ACLs, and segment management traffic.

05 // SECURITY TOOL

Recommended security control

Switch configuration audit

Use Packet Tracer/GNS3 for safe demonstrations.

06 // DEFENSE TOOL

Defense tool

The administrator has not attached a tool yet. This slot will show “Build Soon” until a link or file is configured.

PREMIUMBuild Soon

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DEFENSE TOOL // BUILD SOONThe administrator can attach a file or external tool link from the private admin portal.

AUTHORIZED LEARNING

All attack descriptions are for defensive education. Test scanning, traffic generation, interception, wireless testing, and vulnerable applications only on systems and networks you own or are explicitly authorized to assess.