The Juniper router must be configured to have Gratuitous ARP disabled on all external interfaces.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-217021	JUNI-RT-000150	SV-217021r855889_rule		Medium

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.

STIG	Date
Juniper Router RTR Security Technical Implementation Guide	2024-12-05

Details

Check Text (C-18250r296931_chk)

Review the configuration to determine if gratuitous ARP is disabled on all external interfaces. The following command should not be set to any interface: gratuitous-arp-reply

If gratuitous ARP is enabled on any external interface, this is a finding.

Fix Text (F-18248r296932_fix)

Disable gratuitous ARP on all external interfaces using the following command.

[edit interfaces ge-1/1/0 ]
delete gratuitous-arp-reply