Dell Force10 S55T S55 Configuration Guide FTOS 8.3.5.3 - Page 250
DHCP MAC Source Address Validation, IP+MAC Source Address Validation
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www.dell.com | support.dell.com The DHCP binding table associates addresses assigned by the DHCP servers, with the port on which the requesting client is attached. When IP Source Address Validation is enabled 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. Task Enable IP Source Address Validation Command Syntax ip dhcp source-address-validation Command Mode INTERFACE Note: If IP Source Guard is enabled using the ip dhcp source-address-validation command and there are 187 entries or more in the current DHCP snooping binding table, Source Address Validation (SAV) may not be applied to all entries. To ensure that SAV is applied correctly to all entries, enable the ip dhcp source-address-validation command before adding entries to the binding table. 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. 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. Task Command Syntax Enable DHCP MAC Source Address Validation. ip dhcp snooping verify mac-address Command Mode CONFIGURATION IP+MAC Source Address Validation c s The following feature is available on platforms: , and . 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 validating each attribute individually. IP+MAC Source Address Validation cannot be configured with IP Source Address Validation. Step 1 2 3 Task Allocate at least one FP block to the ipmacacl CAM region. Save the running-config to the startup-config. Reload the system. Command Syntax cam-acl l2acl copy running-config startup-config reload Command Mode CONFIGURATION EXEC Privilege EXEC Privilege 250 | Dynamic Host Configuration Protocol (DHCP)
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