Cisco Certified Network Professional 2025 Complete Practice Test

For IP Source Guard to function effectively, a DHCP snooping binding table is essential. This technology works in conjunction with DHCP snooping, which validates the DHCP messages received on a network to prevent DHCP spoofing attacks.

The DHCP snooping binding table maintains a record of the IP address, MAC address, VLAN, and interface associated with each DHCP client. IP Source Guard utilizes this binding table to enforce security policies by allowing only traffic from IP and MAC addresses that match those entries. Any traffic that does not match an entry in the binding table is dropped, which protects the network from unauthorized access and ensures that IP addresses are being used only by their legitimate owners.

This mechanism allows IP Source Guard to filter traffic at Layer 2 based on the source IP and source MAC addresses, which enhances the overall security posture of the network by preventing IP address spoofing and ensuring that only correctly configured devices can communicate on the network.