HPE Aruba Networking ClearPass Policy Manager (CPPM) uses TCP fingerprinting as a passive profiling method to classify endpoints by analyzing TCP packet headers (e.g., TTL, window size) to identify the operating system (e.g., Windows, Linux). The company in this scenario has Mobility Controllers (MCs), campus APs, and AOS-CX switches, and wants to use CPPM’s TCP fingerprinting capabilities for endpoint classification.

TCP Fingerprinting: This method requires CPPM to receive TCP traffic from endpoints. Since CPPM is not typically inline with network traffic, the traffic must be mirrored to CPPM for analysis. This is often done using a SPAN (Switched Port Analyzer) port or mirror port on a switch or controller.

Option A, "You will need to mirror traffic to one of CPPM’s span ports from a device such as a core routing switch," is correct. For CPPM to perform TCP fingerprinting, it needs to see the TCP traffic from endpoints. This is typically achieved by mirroring traffic from a core routing switch (or another device like an MC) to a SPAN port on the CPPM server. For example, on an AOS-CX switch, you can configure a mirror session with the command mirror session 1 destination interface source vlan to send traffic to CPPM. This is a key consideration for enabling TCP fingerprinting.

Option B, "ClearPass admins will need to provide the credentials of an API admin account to configure on HPE Aruba Networking devices," is incorrect. TCP fingerprinting does not require API credentials. It is a passive profiling method that analyzes mirrored traffic, and no API interaction is needed between CPPM and Aruba devices for this purpose.

Option C, "AOS-CX switches do not offer the support necessary for CPPM to use TCP fingerprinting on wired endpoints," is incorrect. AOS-CX switches support mirroring traffic to CPPM (e.g., using a mirror session), which enables CPPM to perform TCP fingerprinting on wired endpoints. The switch does not need to perform the fingerprinting itself; it only needs to send the traffic to CPPM.

Option D, "TCP fingerprinting of wireless endpoints requires a third-party Mobility Device Management (MDM) solution," is incorrect. TCP fingerprinting is a built-in capability of CPPM and does not require an MDM solution. For wireless endpoints, the MC can mirror client traffic to CPPM (e.g., using a datapath mirror), allowing CPPM to perform TCP fingerprinting.

The HPE Aruba Networking ClearPass Policy Manager 6.11 User Guide states:

"TCP fingerprinting requires ClearPass to receive TCP traffic from endpoints for analysis. A key consideration is that you must mirror traffic to one of ClearPass’s SPAN ports from a device such as a core routing switch or Mobility Controller. For example, on an AOS-CX switch, configure a mirror session with mirror session 1 destination interface source vlan to send traffic to ClearPass for TCP fingerprinting." (Page 248, TCP Fingerprinting Section)

Additionally, the HPE Aruba Networking AOS-8 8.11 User Guide notes:

"For ClearPass to perform TCP fingerprinting on wireless endpoints, the Mobility Controller can mirror client traffic to ClearPass using a datapath mirror. For wired endpoints, an AOS-CX switch can mirror traffic to ClearPass’s SPAN port, enabling TCP fingerprinting without requiring additional support on the switch itself." (Page 351, Device Profiling with CPPM Section)

A rogue radio operating in ad hoc mode with open security can pose several threats to a network. Ad hoc networks allow direct device-to-device communication without centralized control. If such a radio is present within or near a corporate environment, it can potentially be used to create a peer-to-peer network that bypasses corporate security controls, effectively acting as a backdoor into the corporate network for unauthorized users or devices. This can lead to a breach of data security and unauthorized access to network resources.

The scenario involves an AOS-8 Mobility Controller (MC) with a WLAN where a new user group has been added. Users in this group cannot connect to the WLAN, receiving errors indicating no Internet access and inability to reach resources. Exhibit 1 shows the ClearPass Policy Manager (CPPM) Access Tracker record for one user:

CPPM sends an Access-Accept with the VSA Radius:Aruba:Aruba-User-Role user_group4.

The endpoint is classified as "Known," but the user cannot access resources. Exhibit 2 (not provided but described) shows that the AOS device (MC) assigned the user’s client to the "denyall" role, which likely denies all access, explaining the lack of Internet and resource access.

Analysis:

CPPM sends the Aruba-User-Role VSA with the value "user_group4," indicating that the user should be assigned to the "user_group4" role on the MC.

However, the MC assigns the client to the "denyall" role, which typically denies all traffic, resulting in no Internet or resource access.

The issue lies in why the MC did not apply the "user_group4" role sent by CPPM.

Option A, "The AOS device does not have the correct RADIUS dictionaries installed on it to understand the Aruba-User-Role VSA," is incorrect. If the MC did not have the correct RADIUS dictionaries to understand the Aruba-User-Role VSA, it would not process the VSA at all, and the issue would likely affect all users, not just the new user group. Additionally, Aruba-User-Role is a standard VSA in AOS-8, and the dictionaries are built into the system.

Option B, "The AOS device has a server derivation rule configured on it that has overridden the role sent by CPPM," is incorrect. Server derivation rules on the MC can override roles sent by the RADIUS server (e.g., based on attributes like username or NAS-IP), but there is no indication in the scenario that such a rule is configured. If a derivation rule were overriding the role, it would likely affect more users, and the issue would not be specific to the new user group.

Option C, "The clients rejected the server authentication on their side because they do not have the root CA for CPPM’s RADIUS/EAP certificate," is incorrect. If the clients rejected the server authentication (e.g., due to a missing root CA for CPPM’s certificate), the authentication would fail entirely, and CPPM would not send an Access-Accept with the Aruba-User-Role VSA. The scenario confirms that authentication succeeded (Access-Accept was sent), so this is not the issue.

Option D, "The role name that CPPM is sending does not match the role name configured on the AOS device," is correct. CPPM sends the role "user_group4" in the Aruba-User-Role VSA, but the MC assigns the client to the "denyall" role. This suggests that the role "user_group4" does not exist on the MC, or there is a mismatch in the role name (e.g., due to case sensitivity, typos, or underscores vs. hyphens). In AOS-8, if the role specified in the Aruba-User-Role VSA does not exist on the MC, the MC falls back to a default role, which in this case appears to be "denyall," denying all access. The likely problem is that the role name "user_group4" sent by CPPM does not match the role name configured on the MC (e.g., it might be "user-group4" or a different name).

The HPE Aruba Networking AOS-8 8.11 User Guide states:

"When the Mobility Controller receives an Aruba-User-Role VSA in a RADIUS Access-Accept message, it attempts to assign the specified role to the client. If the role name sent by the RADIUS server (e.g., ‘user_group4’) does not match a role configured on the controller, the controller will fall back to a default role, such as ‘denyall,’ which may deny all access. To resolve this, ensure that the role name sent by the RADIUS server matches the role name configured on the controller, accounting for case sensitivity and naming conventions (e.g., underscores vs. hyphens)." (Page 306, Role Assignment Troubleshooting Section)

Additionally, the HPE Aruba Networking ClearPass Policy Manager 6.11 User Guide notes:

"A common issue when assigning roles via the Aruba-User-Role VSA is a mismatch between the role name sent by ClearPass and the role name configured on the Aruba device. If the role name does not match (e.g., ‘user_group4’ vs. ‘user-group4’), the device will not apply the intended role, and the client may be assigned a default role like ‘denyall,’ resulting in access issues. Verify that the role names match exactly in both ClearPass and the device configuration." (Page 290, RADIUS Role Assignment Issues Section)

The scenario involves an AOS-CX switch configured for 802.1X port-access authentication. The configuration defines several roles and their associated VLANs:

port-access role role1 vlan access 11: Role1 assigns VLAN 11.

port-access role role2 vlan access 12: Role2 assigns VLAN 12.

port-access role role3 vlan access 13: Role3 assigns VLAN 13.

port-access role role4 vlan access 14: Role4 assigns VLAN 14.

The switch has 802.1X authentication enabled globally (aaa authentication port-access dot1x authenticator enable). Two ports are configured:

Interface 1/1/1:

vlan access 1: Default VLAN is 1.

aaa authentication port-access critical-role role1: If the RADIUS server is unavailable, assign role1 (VLAN 11).

aaa authentication port-access preauth-role role2: Before authentication, assign role2 (VLAN 12).

aaa authentication port-access auth-role role3: After successful authentication, assign role3 (VLAN 13) unless overridden by a VSA.

Interface 1/1/2: Same configuration as 1/1/1.

Client1 on port 1/1/1:

Client1 authenticates successfully, and CPPM sends an Access-Accept with the VSA Aruba-User-Role: role4.

In AOS-CX, the auth-role (role3) is applied after successful authentication unless the RADIUS server specifies a different role via the Aruba-User-Role VSA. Since CPPM sends Aruba-User-Role: role4, and role4 exists on the switch, Client1 is assigned role4 (VLAN 14), overriding the default auth-role (role3).

Client2 on port 1/1/2:

Client2 does not attempt to authenticate (i.e., does not send 802.1X credentials).

In AOS-CX, if a client does not attempt authentication and no other authentication method (e.g., MAC authentication) is configured, the client is placed in the preauth-role (role2, VLAN 12). This role is applied before authentication or when authentication is not attempted, allowing the client limited access (e.g., to perform authentication or access a captive portal).

Option A, "Client1 = role3; Client2 = role2," is incorrect because Client1 should be assigned role4 (from the VSA), not role3.

Option B, "Client1 = role4; Client2 = role1," is incorrect because Client2 should be assigned the preauth-role (role2), not the critical-role (role1), since the RADIUS server is reachable (Client1 authenticated successfully).

Option C, "Client1 = role4; Client2 = role2," is correct. Client1 gets role4 from the VSA, and Client2 gets the preauth-role (role2) since it does not attempt authentication.

Option D, "Client1 = role3; Client2 = role1," is incorrect for the same reasons as Option A and Option B.

The HPE Aruba Networking AOS-CX 10.12 Security Guide states:

"After successful 802.1X authentication, the AOS-CX switch assigns the client to the auth-role configured for the port (e.g., aaa authentication port-access auth-role role3). However, if the RADIUS server returns an Aruba-User-Role VSA (e.g., Aruba-User-Role: role4), and the specified role exists on the switch, the client is assigned that role instead of the auth-role. If a client does not attempt authentication and no other authentication method is configured, the client is assigned the preauth-role (e.g., aaa authentication port-access preauth-role role2), which provides limited access before authentication." (Page 132, 802.1X Authentication Section)

Additionally, the guide notes:

"The critical-role (e.g., aaa authentication port-access critical-role role1) is applied only when the RADIUS server is unavailable. The preauth-role is applied when a client connects but does not attempt 802.1X authentication." (Page 134, Port-Access Roles Section)

If clients cannot authenticate and there is no record of the authentication attempt in Aruba ClearPass Access Tracker, two possible problems that could cause this symptom are:

The RADIUS shared secret does not match between the switch and CPPM. This mismatch would prevent the switch and CPPM from successfully communicating, so authentication attempts would fail, and no record would appear in Access Tracker.

CPPM does not have a network device profile defined for the switch's IP address. Without a network device profile, CPPM would not recognize authentication attempts coming from the switch and would not process them, resulting in no logs in Access Tracker.

The other options are incorrect because:

Users logging in with the wrong credentials would still generate an attempt record in Access Tracker.

Clients configured to use a mismatched EAP method would also generate an attempt record in Access Tracker.

Clients not configured to trust the root CA certificate for CPPM's RADIUS/EAP certificate might fail authentication, but the attempt would still be logged in Access Tracker.

In an HPE Aruba Networking AOS-8 solution, the Wireless Intrusion Prevention (WIP) system is used to detect and classify rogue Access Points (APs). When a rogue AP is detected, the AOS system provides various pieces of information about the detected radio, such as the SSID, BSSID, match method, match type, confidence level, and the devices that detected the rogue AP. The goal is to locate the physical rogue device, which requires identifying its approximate location in the network environment.

Option A, "The detecting devices," is correct. The "detecting devices" refer to the authorized APs or radios that detected the rogue AP’s signal. This information is critical for locating the rogue device because it provides the physical locations of the detecting APs. By knowing which APs detected the rogue AP and their signal strength (RSSI) readings, you can triangulate the approximate location of the rogue AP. For example, if AP-1 in Building A and AP-2 in Building B both detect the rogue AP, and AP-1 reports a stronger signal, the rogue AP is likely closer to AP-1 in Building A.

Option B, "The match method," is incorrect. The match method (e.g., "Plus one," "Eth-Wired-Mac-Table") indicates how the rogue AP was classified (e.g., based on a BSSID close to a known MAC or its presence on the wired network). While this helps understand why the AP was classified as rogue, it does not directly help locate the physical device.

Option C, "The confidence level," is incorrect. The confidence level indicates the likelihood that the AP is correctly classified as rogue (e.g., 90% confidence). This is useful for assessing the reliability of the classification but does not provide location information.

Option D, "The match type," is incorrect. The match type (e.g., "Rogue," "Suspected Rogue") specifies the category of the classification. Like the match method, it helps understand the classification but does not aid in physically locating the device.

The HPE Aruba Networking AOS-8 8.11 User Guide states:

"When a rogue AP is detected by the Wireless Intrusion Prevention (WIP) system, the ‘detecting devices’ information lists the authorized APs or radios that detected the rogue AP’s signal. This is the most useful information for locating the rogue device, as it provides the physical locations of the detecting APs. By analyzing the signal strength (RSSI) reported by each detecting device, you can triangulate the approximate location of the rogue AP. For example, if AP-1 and AP-2 detect the rogue AP, and AP-1 reports a higher RSSI, the rogue AP is likely closer to AP-1." (Page 416, Rogue AP Detection Section)

Additionally, the HPE Aruba Networking Security Guide notes:

"To locate a rogue AP, use the ‘detecting devices’ information in the AOS Detected Radios page. This lists the APs that detected the rogue AP, along with signal strength data, enabling triangulation to pinpoint the rogue device’s location." (Page 80, Locating Rogue APs Section)

When a device like Device A contacts a secure website and receives a certificate chain from the server, the browser's primary task is to validate the web server's certificate to ensure it is trustworthy. Part of this validation includes checking that the certificate contains a DNS Subject Alternative Name (SAN) that matches the domain name of the website being accessed—in this case, arubapedia.arubanetworks.com. This ensures that the certificate was indeed issued to the entity operating the domain and helps prevent man-in-the-middle attacks where an invalid certificate could be presented by an attacker. The DNS SAN check is critical because it directly ties the digital certificate to the domain it secures, confirming the authenticity of the website to the user's browser.