Layer 2 Security Best Practices

Layer 2 Security Best Practices

Layer 2 Security Overview

Layer 2 attacks target the data link layer, exploiting switches and VLANs. Common attacks include MAC flooding, ARP spoofing, VLAN hopping, and spanning tree attacks. Proper Layer 2 security is foundational for network security.

Layer 2 Security

VLAN Security

Secure VLANs through proper segmentation, disabling unused VLANs, implementing private VLANs, using VLAN access control lists, and avoiding VLAN 1 for user traffic. Configure trunk ports carefully with explicit VLAN allowlists.

Port Security

Implement port security limiting MAC addresses per port, enabling sticky MAC learning, configuring violation actions (shutdown, restrict, protect), and monitoring port security violations. Port security prevents MAC flooding and unauthorized device connections.

ARP Security

Prevent ARP spoofing through Dynamic ARP Inspection (DAI), DHCP snooping, static ARP entries for critical systems, and ARP monitoring. DAI validates ARP packets against DHCP snooping database preventing man-in-the-middle attacks.

Additional Protections

Enable BPDU guard preventing spanning tree attacks, configure root guard protecting spanning tree topology, implement DHCP snooping preventing rogue DHCP servers, and use IP Source Guard preventing IP spoofing attacks.

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