The RUCKUS ICX perimeter router must be configured to have Proxy ARP disabled on all external interfaces.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-273645	SRG-NET-000364-RTR-000112	RCKS-RTR-000780	SV-273645r1110946_rule	2025-06-03	1

Description
When Proxy ARP is enabled on a Cisco router, it allows that router to extend the network (at layer 2) across multiple interfaces (LAN segments). Because proxy ARP allows hosts from different LAN segments to look like they are on the same segment, proxy ARP is only safe when used between trusted LAN segments. Attackers can leverage the trusting nature of proxy ARP by spoofing a trusted host and then intercepting packets. Proxy ARP should always be disabled on router interfaces that do not require it, unless the router is being used as a LAN bridge.

Description

When Proxy ARP is enabled on a Cisco router, it allows that router to extend the network (at layer 2) across multiple interfaces (LAN segments). Because proxy ARP allows hosts from different LAN segments to look like they are on the same segment, proxy ARP is only safe when used between trusted LAN segments. Attackers can leverage the trusting nature of proxy ARP by spoofing a trusted host and then intercepting packets. Proxy ARP should always be disabled on router interfaces that do not require it, unless the router is being used as a LAN bridge.

ℹ️ Check
This requirement is not applicable for the DODIN Backbone. Review the router configuration to determine if IP Proxy ARP has been enabled (see below): ip proxy-arp Note: By default, Proxy ARP is disabled globally. If IP Proxy ARP is enabled, this is a finding.

✔️ Fix
This requirement is not applicable for the DODIN Backbone. Disable IP Proxy ARP as shown in the example below: ICX(config)# no ip proxy-arp