The Cisco router must be configured to have Gratuitous ARP disabled on all external interfaces.
An XCCDF Rule
Description
A gratuitous ARP is an ARP broadcast in which the source and destination MAC addresses are the same. It is used to inform the network about a host IP address. A spoofed gratuitous ARP message can cause network mapping information to be stored incorrectly, causing network malfunction.
- ID
- SV-216563r856182_rule
- Version
- CISC-RT-000150
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Disable gratuitous ARP as shown in the example below:
R5(config)#no ip gratuitous-arps