Dell Configuration Guide for the S4048–ON System 9.14.2.4

A spoofed IP packet is one in which the IP source address is strategically chosen to disguise the attacker. For example, using ARP spoofing, an attacker can assume a legitimate client’s identity and receive traffic addressed to it. Then the attacker can spoof the client’s IP address to interact with other clients.

The DHCP binding table associates addresses the DHCP servers assign with the port or the port channel interface on which the requesting client is attached and the VLAN the client belongs to. When you enable IP source address validation on a port, the system verifies that the source IP address is one that is associated with the incoming port and optionally that the client belongs to the permissible VLAN. If an attacker is impostering as a legitimate client, the source address appears on the wrong ingress port and the system drops the packet. If the IP address is fake, the address is not on the list of permissible addresses for the port and the packet is dropped. Similarly, if the IP address does not belong to the permissible VLAN, the packet is dropped.

To enable IP source address validation, use the following command.