Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 345

DHCP MAC Source Address Validation DHCP MAC source address validation (SAV) validates a DHCP packet's source hardware address against the client hardware address field (CHADDR) in the payload. The system ensures that the packet's source MAC address is checked against the CHADDR field in the DHCP header only for packets from snooped VLANs. • Enable DHCP MAC SAV. CONFIGURATION mode ip dhcp snooping verify mac-address Enabling IP+MAC Source Address Validation IP source address validation (SAV) validates the IP source address of an incoming packet against the DHCP snooping binding table. IP+MAC SAV 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 SAV with IP SAV. 1 Allocate at least one FP block to the ipmacacl CAM region. CONFIGURATION mode cam-acl l2acl 2 Save the running-config to the startup-config. EXEC Privilege mode copy running-config startup-config 3 Reload the system. EXEC Privilege reload 4 Enable IP+MAC SAV. INTERFACE mode ip dhcp source-address-validation ipmac 5 Enable IP source address validation with VLAN option. INTERFACE mode ip dhcp source-address-validation ipmac vlan vlan-id The system creates an ACL entry for each IP+MAC address pair in the binding table and applies it to the interface. To display the IP+MAC ACL for an interface for the entire system, use the show ip dhcp snooping source-addressvalidation [interface] command in EXEC Privilege mode. Viewing the Number of SAV Dropped Packets The following output of the show ip dhcp snooping source-address-validation discard-counters command displays the number of SAV dropped packets. Dell>show ip dhcp snooping source-address-validation discard-counters deny access-list on TenGigabitEthernet 0/0 Total cam count 1 deny count (0 packets) deny access-list on TenGigabitEthernet 0/1 Dynamic Host Configuration Protocol (DHCP) 345