Pass the HP Aruba Certified Switching Expert HPE7-A08 Questions and answers with Dumpstech

Downloadable User Roles (DUR) are a key component of Aruba ' s Dynamic Segmentation. Instead of manually defining roles on every switch, the switch downloads the role definition (VLAN, ACLs, QoS) dynamically from Aruba ClearPass via HTTPS .

The HTTPS Connection: When a user authenticates, ClearPass sends a RADIUS attribute containing the role name. The switch then initiates an HTTPS connection to the ClearPass server to fetch the full details of that role.

Certificate Trust: Because this download happens over HTTPS, the AOS-CX switch acts as an HTTPS Client . For the connection to be established, the switch must trust the SSL/TLS certificate presented by ClearPass.

Validation Requirement: If the switch does not have the correct CA Certificate installed, or if the HTTPS client certificate configuration is missing or incorrect, the TLS handshake will fail. The switch will be unable to download the role, and the user will typically be placed in a " denyall " or " initial " role. Therefore, verifying the HTTPS/TLS certificate configuration on the switch is a primary troubleshooting step for DUR.

Why other options are incorrect:

Option B: DUR does not use the REST API of the switch; it uses a standard HTTPS GET request to ClearPass.

Option C: SNMP is for monitoring and is not involved in the real-time delivery of user roles.

Option D: While the user-role name must match, the reason a DUR fails to load is almost always the transport mechanism (RADIUS or HTTPS), not the role name configuration itself.

LACP (Link Aggregation Control Protocol) modes can be active or passive. When two switches are both configured in passive mode, no LACP packets are initiated, causing the link aggregation to fail or go into a block state.

Changing one side from passive to active causes that switch to initiate LACP negotiation, resolving the block state.

Changing to static mode disables LACP negotiation, which is not recommended unless both sides are static.

Changing timeout does not solve LACP block issues caused by mode mismatches.

Therefore, changing one switch’s LACP mode from passive to active is necessary to resolve the block.

Valid Network Analytics Engine (NAE) agent actions include:

Running CLI commands (Option A), allowing automated command execution for remediation or data collection.

Generating local system logs (Option C) for event tracking and audit purposes.

Other options:

Generating SNMP traps (B) and starting/stopping packet captures (D) are not typical NAE actions.

Creating a new TAC case (E) is an external process, not an automated NAE action.

To avoid split-brain scenarios in VSF stacks, the VSL split-detect mgrep command is used to enable multicast group detection over the Virtual Switching Link (VSL). This helps detect when the stack links are down or partitioned, triggering appropriate failover or shutdown mechanisms.

Options like vsf start-auto-stacking, vsf secondary-member 2, or vsf conductor-member 2 are related to stack initialization and member roles but do not address split-brain detection directly.

Hence, enabling split-detect with mgrep is the best practice for VSF stack stability.

To protect a network from Layer 2 man-in-the-middle attacks, AOS-CX switches utilize two closely related security features: DHCP Snooping and Dynamic ARP Protection .

DHCP Snooping: This feature acts as a firewall between untrusted hosts and trusted DHCP servers. When enabled, the switch categorizes ports as either trusted (connected to a legitimate DHCP server or another switch) or untrusted (connected to end-user devices). If a " malicious " DHCP server on an untrusted port attempts to send a DHCP OFFER or ACK message, the switch drops the packet.

The Snooping Binding Table: As a byproduct of monitoring legitimate DHCP exchanges, the switch builds a DHCP Snooping Binding Table . This table is a " source of truth " that maps a client ' s MAC address to its assigned IP address and the specific physical port it is connected to.

Dynamic ARP Protection: ARP poisoning (or spoofing) occurs when an attacker sends fake ARP messages to link their MAC address with the IP address of a legitimate server or gateway. When ARP protection is enabled, the switch intercepts all ARP packets on untrusted ports and validates them against the DHCP Snooping Binding Table . If the MAC-to-IP mapping in the ARP packet does not match the entry in the table, the packet is discarded.

Integration: These two features must work together. Without the binding table created by DHCP Snooping, ARP Protection has no data to validate against. This combination ensures that only the device that legitimately received an IP via DHCP can claim that IP in ARP responses.

The exhibit shows a configuration for a Route Map named BGP-EXPORT. To identify the correct statement, we must analyze the specific BGP attributes being manipulated in the sequence entries.

Analyzing Sequence 10:

Match: It looks for network prefixes defined in an IP prefix-list named bgp-export.

Set: It executes the command as-path prepend 65345 65345 65345.

AS Path Prepending: In BGP, the " Shortest AS Path " is one of the primary decision factors in the Best Path Selection Algorithm. AS Path Prepending is a technique used by network administrators to make a specific route appear " less desirable " to external neighbors. By adding multiple instances of an AS number (in this case, AS 65345 is added three times) to the existing AS Path, the switch artificially increases the length of the path.

Conclusion for Statement B: Because the route map prepends the AS path for the matched prefixes, the resulting BGP update sent to neighbors will contain an AS path that is significantly longer than the default (which would normally just include the local AS). Therefore, statement B is true.

Evaluating other options:

Option A: This is technically incorrect syntax. Route maps are applied to BGP neighbors using the command neighbor [IP] route-map BGP-EXPORT out (for export) or in (for import). There is no " remote-as export " command for binding route maps.

Option C: There is no set metric or set med command visible in the output. MED (Multi-Exit Discriminator) is a different attribute used to influence inbound traffic from an adjacent AS.

Option D: This is a conceptual error. IP prefix-lists are used to match IP addresses and subnet masks (the " prefixes " ). AS Path Lists (as seen in Seq 100) or regular expressions are used to match AS paths. You do not configure the path itself inside a prefix-list.

In AOS-CX QoS architecture, the switch uses a scheduler to determine which hardware queues receive service. A common best practice is to use a Hybrid Queuing Model .

Strict Priority (SP) and Starvation: By default, if a queue is set to Strict Priority (usually Queue 7 for voice), the switch will service that queue exclusively as long as it has data. If the high-priority traffic is sustained (due to a burst or a misconfiguration/attack), the lower-priority queues (Queues 0–5) will never be serviced. This is known as starvation .

The Role of Shaping: To prevent an SP queue from monopolizing the entire link bandwidth, you can apply a shaper to that specific high-priority queue. A shaper sets a maximum bandwidth limit (in kbps or as a percentage) that the queue is allowed to consume.

Mechanism: By shaping Queue 7, even if it has a constant stream of traffic, it will be " throttled " once it hits the shaper limit. This forced " quiet time " allows the scheduler to move down and service the lower-priority queues using DWRR (Deficit Weighted Round Robin) logic, ensuring that data traffic (like web or email) is not completely dropped.

Evaluating Other Options:

Option A: You can only apply one queuing profile per interface in AOS-CX.

Option B: Replacing SP with DWRR entirely would solve starvation, but it would remove the low-latency guarantee required for Voice traffic.

Option D: " Weight " applies only to DWRR/WFQ queues. SP queues do not have a weight because they are always " first in line " by definition.

To prevent rogue DHCP servers in a VLAN, DHCP snooping authorized-server commands are used to specify trusted DHCP servers allowed to respond.

Option A (dhcpv4-snooping trust 10.100.100.10) configures a trusted port, but it is not VLAN specific and not precise enough for this purpose.

Enabling DHCP snooping globally and on VLAN or interface (Options C and D) are prerequisites but do not prevent rogue servers unless authorized servers are defined.

Option B correctly enables an authorized DHCP server IP on VLAN 30, blocking unauthorized DHCP responses.

When establishing eBGP peering between devices that are not directly connected, the TTL (Time To Live) value of the BGP packets must be increased to allow them to traverse multiple hops. This is achieved by configuring ebgp-multihop, which increases the TTL beyond the default value of 1.

next-hop-self changes the BGP next-hop attribute but is not required for multihop eBGP.

route-reflector is a BGP design feature unrelated to multihop.

address-family ipv4 external is not a standard command on Aruba CX switches.

Therefore, to successfully peer eBGP sessions across multiple hops, ebgp-multihop must be configured.