V-269960

Discussion

IP Source Guard provides source IP address filtering on a Layer 2 port to prevent a malicious host from impersonating a legitimate host by assuming the legitimate host's IP address. The feature uses dynamic DHCP snooping and static IP source binding to match IP addresses to hosts on untrusted Layer 2 access ports. Initially, all IP traffic on the protected port is blocked except for DHCP packets. After a client receives an IP address from the DHCP server, or after static IP source binding is configured by the administrator, all traffic with that IP source address is permitted from that client. Traffic from other hosts is denied. This filtering limits a host's ability to attack the network by claiming a neighbor host's IP address.

Check Content

Review the Dell OS10 Switch configuration and verify that SAV is enabled on all user-facing or untrusted access switch ports.

Verify that DHCP snooping is enabled globally:

ip dhcp snooping

Verify that interfaces attached to trusted DHCP servers are configured:

interface ethernet 1/1/4
  ip dhcp snooping trust

Enable source IP and MAC address validation in INTERFACE mode for each untrusted and user-facing port:

ip dhcp snooping source-address-validation ipmac

If the switch does not have DHCP snooping is enabled globally, a trusted DHCP server port specified, and Source Address Validation enabled for all user-facing or untrusted access switch ports, this is a finding.