The Aruba Certified Network Security Expert Written Exam (HPE6-A84)

EAP (Extensible Authentication Protocol) is a framework that allows different authentication methods to be used for network access. EAP is used for RADIUS/EAP authentication, which is a common method for authenticating domain users on domain computers using certificates. EAP requires that the RADIUS server, such as ClearPass Policy Manager (CPPM), validates the certificates presented by the clients and verifies their identity against an identity source, such as Windows AD. Therefore, the root certificate for the Windows CA that issues the certificates to the clients should have the EAP usage in the ClearPass CA Trust list.

Radsec (RADIUS over TLS) is a protocol that allows secure and encrypted communication between RADIUS servers and clients using TLS. Radsec is used for encrypting all communications between CPPM and the domain controllers, which act as RADIUS clients. Radsec requires that both the RADIUS server and the RADIUS client validate each other’s certificates and establish a TLS session. Therefore, the root certificate for the Windows CA that issues the certificates to the domain controllers should have the Radsec usage in the ClearPass CA Trust list.

Aruba Central can provide visibility and profiling of clients using the Client Insights feature, which is an AI-powered solution that uses native infrastructure telemetry to identify and classify clients based on their OS and general category. This feature does not require any additional hardware or software, such as gateways, IP helpers, or packet sniffers. It works by collecting and analyzing data from the Aruba APs and AOS-CX switches that are managed by Aruba Central. You can find more information about Client Insights in the Visibility and profiling solutions | HPE Aruba Networking page and the Clients Profile - Aruba page.

BPDU (Bridge Protocol Data Unit) is a message that is exchanged between switches to maintain the spanning tree topology and prevent loops. BPDU protection and BPDU filtering are two features that can be configured on AOS-CX switch ports to enhance security and performance.

BPDU protection is a feature that disables a port if it receives a BPDU, indicating that an unauthorized switch or device has been connected to the port. BPDU protection is typically used on edge ports, which are ports that connect to end devices such as PCs or printers, and are not expected to receive BPDUs. BPDU protection prevents rogue devices from connecting to the network and affecting the spanning tree topology.

BPDU filtering is a feature that prevents a port from sending or receiving BPDUs, effectively isolating the port from the spanning tree topology. BPDU filtering is typically used on inter-switch ports, which are ports that connect to other switches, for specialized use cases such as creating a separate spanning tree domain or reducing the overhead of BPDUs. BPDU filtering should be used with caution, as it can create loops or inconsistencies in the network.

You can find more information about how to configure BPDU protection and BPDU filtering on AOS-CX switch ports in the [Configuring Spanning Tree Protocol - Aruba] page and the [AOS-CX Switching Configuration Guide] page. The other options are not correct because they either use BPDU protection or BPDU filtering on the wrong type of ports or for the wrong purpose. For ex ample, using BPDU protection on inter-switch ports would disable the ports if they receive BPDUs, which are expected in normal operation. Using BPDU filtering on edge ports would allow rogue devices to connect to the network and create loops or affect the spanning tree topology.

This is because a parameter is a variable that can be defined and modified by the user or the script, and can be used to customize the behavior and output of the NAE script. A parameter can be referred to by using the syntax self ^ramsfname], where ramsfname is the name of the parameter.

By defining a parameter for the RADIUS server, you can make the NAE script more flexible and adaptable to different scenarios and switches. The parameter can be set to a default value, such as cp.acnsxtest.local, but it can also be changed by the user or the script based on the network conditions and requirements. For example, the user can select a different hostname or IP address for the monitored RADIUS server when they create an agent from the script, or the script can automatically detect and update the parameter based on the switch configuration. This way, the NAE script can monitor statistics from any RADIUS server defined on the switch without hard-coding the server name or IP address in the monitor URI.

A. Use this variable, %{radius-ipV when defining the monitor URI in the NAE agent script. This is not a valid recommendation because %{radius-ipV is not a valid variable in NAE scripts. Variables in NAE scripts are prefixed with self ^ramsfname], not with %. Moreover, radius-ipV is not a predefined variable that contains the RADIUS server name or IP address, but rather a generic term that could refer to any IP version.

C. Use a callback action to collect the name of any RADIUS servers defined on the switch at the time the agent is created. This is not a bad recommendation, but it is not as good as defining a parameter. A callback action is a feature that allows an NAE script to execute a command on the switch and collect its output for further processing or display. A callback action can be used to collect the name of any RADIUS servers defined on the switch by executing a command such as show radius-server or show running-config radius-server and parsing its output. However, a callback action might not be as fast or reliable as using a parameter, as it depends on the availability and responsiveness of the switch and its CLI.

D. Make the script editable so that admins can edit it on demand when they are creating scripts. This is not a good recommendation because making the script editable exposes it to potential errors or modifications that could affect its functionality or performance. Making the script editable also requires more effort and expertise from the admins, who might not be familiar with NAE scripting syntax or logic. Moreover, making the script editable does not future proof it, as it does not allow for dynamic changes or updates based on network conditions or requirements.

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The subnet mask in rule 3 of the “medical-mobile” policy is currently 255.255.252.0, which means that the rule denies access to the 10.1.12.0/22 subnet as well as the adjacent 10.1.16.0/22 subnet  1 . This is not consistent with the scenario requirements, which state that only the 10.1.12.0/22 subnet should be denied access, while the rest of the 10.1.0.0/16 range should be permitted access.

To fix this issue, the subnet mask in rule 3 should be changed to 255.255.248.0, which means that the rule only denies access to the 10.1.8.0/21 subnet, which includes the 10.1.12.0/22 subnet  1 . This way, the rule matches the scenario requirements more precisely.

A custom NAE script is a Python script that defines the monitors, the alert-trigger logic, and the remedial actions for an NAE agent. A monitor is a URI that specifies the data source and the data type that the NAE agent should collect and analyze. For example, to monitor the ARP inspection statistics on a VLAN, the monitor URI would be something like this:

where < vlan-id > is the ID of the VLAN to be monitored.

To allow the admins to select the correct VLAN ID for the agent to monitor when they create the agent, you need to define a VLAN ID parameter in the NAE script. A parameter is a variable that can be set by the user when creating or modifying an agent. A parameter can be referenced in other parts of the script by using the syntax ${parameter-name}. For example, to define a VLAN ID parameter and reference it in the monitor URI, you would write something like this:

This way, when the admins create or modify the agent, they can enter the VLAN ID that they want to monitor, and the NAE script will use that value in the monitor URI.

You can find more information about how to write custom NAE scripts and use parameters in the  NAE Scripting Guide

To configure CPPM to collect information from Intune on demand during the authentication process, you need to use the Intune extension for ClearPass. This extension allows ClearPass to query Intune for device compliance and configuration information using the Intune API.  To use this extension, you need to register an app in Azure AD and grant it the required permissions to access Intune 1

The Intune extension uses the device ID as the key to query Intune for device information. The device ID is a unique identifier that is assigned by Intune to each enrolled device. The device ID can be obtained from the client certificate that is used for EAP-TLS authentication.  Therefore, the certificates issued to clients must include the Intune ID in the subject name, so that ClearPass can extract it and use it to query Intune 2

The certificates issued to clients do not need to be issued by a well-known, trusted CA, as long as ClearPass trusts the CA that issued them. The certificates do not need to include the client MAC address in the subject name, as this is not relevant for querying Intune. The certificates do not need to be issued by a ClearPass Onboard CA, as this is not a requirement for using the Intune extension.

According to the Aruba Cloud Authentication and Policy Overview 1 , one of the prerequisites for configuring Cloud Authentication and Policy is to configure Device Insight (client profile) tags in Central. Device Insight tags are used to identify and classify IoT devices based on their behavior and characteristics.  These tags can then be mapped to client roles, which are defined in the WLAN configuration for IAPs 2 . Client roles are used to enforce role-based access policies for the IoT devices. Therefore, option B is the correct answer.

Option A is incorrect because NetConductor is not related to Cloud Authentication and Policy. NetConductor is a cloud-based network management solution that simplifies the deployment and operation of Aruba Instant networks.

Option C is incorrect because integrating Aruba ClearPass Policy Manager (CPPM) and Device Insight is not a prerequisite for setting up the device role mappings. CPPM and Device Insight can work together to provide enhanced visibility and control over IoT devices, but they are not required for Cloud Authentication and Policy.

Option D is incorrect because creating global role-to-role firewall policies in Central is not a prerequisite for setting up the device role mappings. Global role-to-role firewall policies are used to define the traffic rules between different client roles across the entire network, but they are not required for Cloud Authentication and Policy.

A profile conflict occurs when ClearPass Policy Manager (CPPM) detects a change in the device category or OS family of an endpoint that has been previously profiled. This could indicate that someone has spoofed the MAC address of a legitimate device and is trying to gain unauthorized access to the network. For example, if an endpoint that was previously profiled as a Printer suddenly shows a new profile of Computer, this could be a sign of an attack. You can find more information about profile conflicts and how to resolve them in the ClearPass Policy Manager User Guide1. The other options are not necessarily signs of unauthorized access, as they could have other explanations. For example, multiple DHCP options under the fingerprints could indicate that the device has connected to different networks or subnets, an Unknown status could indicate that the device has not been authenticated yet, and a lack of hostname or a random hostname could indicate that the device has not been configured properly or has been reset to factory settings.