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The Juniper EX switch must be configured to enable Dynamic Address Resolution Protocol (ARP) Inspection (DAI) on all user VLANs with active access interfaces.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-253961JUEX-L2-000140SV-253961r1212017_ruleCCI-002385medium
Description
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 (e.g., access interface with a valid binding or a trunked interface), the switch forwards the packet without any checks. On untrusted interfaces, the switch forwards the packet only if it is valid.
STIGDate
Juniper EX Series Switches Layer 2 Switch Security Technical Implementation Guide2026-06-03

Related Frameworks

1 mapping across 4 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (13) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

MON-01Continuous Monitoring
1.00
MON-01.1Intrusion Detection & Prevention Systems (IDS & IPS)
1.00
MON-01.3Inbound & Outbound Communications Traffic
1.00
MON-01.4System Generated Alerts
1.00
MON-01.8Security Event Monitoring
1.00
NET-01Network Security Controls (NSC)
1.00
NET-02Layered Network Defenses
1.00
SEA-01Secure Engineering Principles
1.00
SEA-02Alignment With Enterprise Architecture
1.00
CAP-01Capacity & Performance Management
0.50

+3 more (top 10 by confidence shown)

NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (36) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

AC-10Concurrent Session Control
1.00
AC-17(9)Disconnect or Disable Access
1.00
AC-2(4)Automated Audit Actions
1.00
AC-3Access Enforcement
1.00
AC-4Information Flow Enforcement
1.00
AC-6(9)Log Use of Privileged Functions
1.00
AU-12Audit Record Generation
1.00
AU-3Content of Audit Records
1.00
AU-5Response to Audit Logging Process Failures
1.00
CM-11(2)Software Installation with Privileged Status
1.00

+26 more (top 10 by confidence shown)

CCI1 mapping
CCI-002385
1.00
NIST CSF 2.00 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (3) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

DE.CM-01
1.00
PR.IR-01
1.00
PR.IR-04
0.50

Who does this work

12 NICE work roles and 9 EC-Council certifications.

This is an inference across published mappings, not a single claim by anyone. This check maps to a control, which maps to a Cybersecurity Framework outcome, which NIST assigns to the work roles below. EC-Council separately maps its certifications to those same roles.

A certification prepares someone for a role. It is not evidence that a holder is qualified, and neither NIST nor EC-Council has stated that any certification here addresses this check.

Work-role assignments published by NIST (NICE Framework Components 2.2.0 and the CSF 2.0 OLIR crosswalk). Certification mappings published by EC-Council.

Details

Check Text (C-253961r1212017_chk)

Review the switch configuration to verify that DAI is enabled on all user VLANs with active access interfaces. Configuring DAI automatically enables DHCP snooping. Devices such as printers, servers, and VoIP phones are under enterprise control and connected to controlled access interfaces (802.1x, Static MAC Bypass, or MAC RADIUS), making them trusted sources in nonuser-facing VLANs. Verify DAI on user-facing or untrusted VLANs with active access interfaces. user@host> show configuration vlans <untrusted VLAN name> { vlan-id <VLAN ID>; forwarding-options { dhcp-security { arp-inspection; } } } Note: DAI depends on DHCP snooping or static MAC address bindings. This check is not applicable to switches configured with user-facing or untrusted VLANs merely for inclusion in trunks (e.g., core or distribution switch without access interfaces assigned to user-facing or untrusted VLANs). If DAI is not enabled on all user VLANs with active access interfaces, this is a finding.

Fix Text (F-57364r1212016_fix)

Configure the switch to have DAI enabled on all user VLANs with active access interfaces. 1. Enter configuration mode. 2. Configure user-facing or untrusted VLANs with active access interfaces with DAI. 3. Commit the configuration. user@host> configure Entering configuration mode user@host# set vlans <untrusted VLAN name> vlan-id <untrusted VLAN ID> user@host# set vlans <untrusted VLAN name> forwarding-options dhcp-security arp-inspection user@host# commit commit complete