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CCNA Security Exam Cram (Exam IINS 640-553) by Eric L. Stewart

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VLAN Hopping Attacks

EXAM ALERT

Be sure to review basic virtual LAN (VLAN) and IEEE 802.1Q trunk configuration and operation from the prerequisite CCNA material.

VLAN hopping attacks occur when an attacker tricks a switch into allowing traffic to hop to a different VLAN than the VLAN assigned to the port to which they are connected. Normally, routers are required to route traffic between VLANs at layer 3.

NOTE

Recall “router-on-a-stick” and inter-VLAN routing from your CCNA studies. For traffic to move between VLANs, it needs to be routed either by a router integral to the switch, or by an external router attached to the switch by a trunk port. When diagramming the latter scenario, the router appears connected to the switch by a ...

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