Free DISA STIG and SRG Library | Vaulted

V-101137

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

Finding ID
CISC-L2-000150
Rule ID
SV-110241r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-NET-000362-L2S-000027
CCI
CCI-002385
Target Key
(None)
Documentable
No
Discussion

DAI intercepts 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.

Fix Text

Configure the switch to have DAI enabled on all user VLANs as shown in the example below: SW2(config)#ip arp inspection vlan 2,4-8,11

Check Content

Review the switch configuration to verify that the DAI feature is enabled on all user VLANs: hostname SW2 … … … ip arp inspection vlan 2,4-8,11 Note: DAI depends on the entries in the DHCP snooping binding database to verify IP-to-MAC address bindings in incoming ARP requests and ARP responses. If DAI is not enabled on all user VLANs, this is a finding.