Dell Force10 MXL Blade MXL 10/40GbE Switch IO Module Configuration Guide - Page 187
IP Source Address Validation, field in the DHCP header only for packets from snooped VLANs.
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IP Source Address Validation IP source address validation prevents IP spoofing by forwarding only IP packets that have been validated against the DHCP binding table. 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 assigned by the DHCP servers, with the port on which the requesting client is attached. 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. If an attacker is impostering as a legitimate client, the source address appears on the wrong ingress port and the system drops the packet. Likewise, if the IP address is fake, the address will not be on the list of permissible addresses for the port, and the packet is dropped. To enable IP source address validation, follow this step: Task Enable IP Source Address Validation Command Syntax ip dhcp source-address-validation Command Mode INTERFACE DHCP MAC Source Address Validation DHCP MAC source address validation validates a DHCP packet's source hardware address against the client hardware address field (CHADDR) in the payload. FTOS Release 8.2.1.1 ensures that the packet's source MAC address is checked against the CHADDR field in the DHCP header only for packets from snooped VLANs. To enable DHCP MAC source address validation, follow this step: Task Enable DHCP MAC Source Address Validation. Command Syntax ip dhcp snooping verify mac-address Command Mode CONFIGURATION IP+MAC Source Address Validation IP source address validation validates the IP source address of an incoming packet against the DHCP snooping binding table. IP+MAC source address validation ensures that the IP source address and MAC source address are a legitimate pair, rather than validating each attribute individually. You cannot configure IP+MAC source address validation with IP source address validation. Dynamic Host Configuration Protocol (DHCP) | 185
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