The layer 2 switch must have Dynamic Address Resolution Protocol (ARP) Inspection (DAI) enabled on all user VLANs.

From Layer 2 Switch Security Requirements Guide

Associated with: CCI-002385

SV-76675r1_rule The layer 2 switch must have Dynamic Address Resolution Protocol (ARP) Inspection (DAI) enabled on all user VLANs.

Vulnerability discussion

DAI intercepts Address Resolution Protocol (ARP) requests and verifies that each of these packets has a valid IP-to-MAC address binding before updating the local ARP cache and before forwarding the packet to the appropriate destination. Invalid ARP packets are dropped and logged. DAI determines the validity of an ARP packet based on valid IP-to-MAC address bindings stored in the DHCP snooping binding database. If the ARP packet is received on a trusted interface, the switch forwards the packet without any checks. On untrusted interfaces, the switch forwards the packet only if it is valid.

Check content

Review the switch configuration to verify that Dynamic Address Resolution Protocol (ARP) Inspection (DAI) feature is enabled on all user VLANs. If DAI is not enabled on all user VLANs, this is a finding.

Fix text

Configure the switch to have Dynamic Address Resolution Protocol (ARP) Inspection (DAI) enabled on all user VLANs.

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.