View Full Juniper JN0-253 Exam Dumps and Practice Test Dumps.

 

Question 261

Which Junos CLI command allows an administrator to search for configuration statements or operational commands containing a specific keyword?

1. help apropos
2. show system help
3. search command tree
4. find configuration string

Correct Answer: 1

Explanation

The help apropos command in Junos OS is a powerful diagnostic and lookup tool. When executed with a specific keyword, it searches the entire Junos command hierarchy and configuration database to locate matching operational commands or configuration statements. This is extremely helpful for engineers who know what function they want to perform but need assistance finding the exact CLI syntax or hierarchical path.

Question 262

What is the primary operational function of BGP community tags in enterprise routing policies?

1. Encrypting BGP session TCP transmission headers
2. Grouping prefixes to apply routing policy actions across multiple routers
3. Translating private autonomous system numbers to global public values
4. Replacing standard IPv4 address blocks with IPv6 formatting

Correct Answer: 2

Explanation

BGP communities are optional transitive attributes attached to route advertisements as architectural tags or labels. Network administrators utilize community strings to categorize groups of prefixes based on geographical location, business logic, or traffic engineering rules. Downstream routers can evaluate these tags within their routing policies to apply consistent filtering, preference adjustments, or propagation controls without needing explicit individual prefix lists.

Question 263

How does the hierarchical configuration structure of Junos OS benefit network administrators?

1. By requiring raw binary file editing for every interface configuration
2. By organizing configuration parameters into logical, intuitive parent-child structural blocks
3. By eliminating the need for any historical rollback backup archives
4. By executing automatic firmware flashing on every system boot

Correct Answer: 2

Explanation

Junos OS utilizes a structured, hierarchical configuration syntax where statements are grouped into logical parent-child relationships (such as system, interfaces, protocols, and policy-options). This modular design mirrors actual network architecture, making configurations easier to read, audit, and modify compared to flat configuration models. It also prevents syntax ambiguity and simplifies automation script generation.

Question 264

What is the primary operational difference between OSPF Type 1 and Type 2 External routes?

1. Type 1 routes add external metric costs to internal path costs, whereas Type 2 routes consider only the external metric cost
2. Type 1 routes are strictly restricted to stub areas, while Type 2 routes flood everywhere
3. Type 1 routes use UDP transport, while Type 2 routes use TCP socket connections
4. Type 1 routes require manual static peering configurations on all routers

Correct Answer: 1

Explanation

OSPF external routes imported by an ASBR are categorized as either Type 1 or Type 2. Type 1 external route metrics accumulate internal path costs along with the external seed metric, providing an accurate total cost calculation across the network topology. Type 2 external routes ignore internal path costs, evaluating only the external seed cost regardless of how far the destination resides within the OSPF domain. Type 2 is the default external route type in OSPF.

Question 265

Which technology allows Juniper Mist to deliver real-time client analytics and indoor location tracking without requiring GPS hardware?

1. Ultrasonic acoustic sound wave beacons
2. Virtual Bluetooth Low Energy (vBLE) multi-antenna array
3. High-frequency radar dish scanning arrays
4. Cellular tower triangulation modules

Correct Answer: 2

Explanation

Juniper Mist incorporates a patented multi-element virtual Bluetooth Low Energy antenna array inside its access points. By utilizing machine learning algorithms to process RSSI readings from client devices across multiple access points, the Mist platform computes precise indoor location tracking, asset monitoring, and proximity wayfinding without needing physical battery-powered beacon hardware overlays.

Question 266

In Junos routing policies, what does the as-path regular expression match modifier .* represent?

1. Exact match of a single specific autonomous system number
2. Zero or more occurrences of any autonomous system sequence
3. A mandatory termination flag for route advertisements
4. An explicit deny action for external path filtering

Correct Answer: 2

Explanation

When constructing regular expressions for BGP AS-Path matching in Junos routing policies, the dot (.) matches any single character (representing any AS number), and the asterisk (*) specifies zero or more occurrences of the preceding element. Therefore, .* acts as a wildcard matching any sequence or length of autonomous systems, frequently used in catch-all policy terms.

Question 267

Which Spanning Tree feature protects against loops by putting a port into a loop-inconsistent state if BPDUs suddenly stop arriving on a point-to-point link?

1. Root Guard
2. BPDU Guard
3. Loop Guard
4. Port Fast

Correct Answer: 3

Explanation

Spanning Tree Loop Guard is designed to prevent bridging loops caused by unidirectional link failures on point-to-point connections. If a link stops receiving BPDUs due to a physical transmission fault, Loop Guard prevents alternate or root ports from incorrectly transitioning into a forwarding state, immediately forcing them into a blocking loop-inconsistent state instead.

Question 268

What is the primary operational advantage of using configuration groups (groups) in Junos OS?

1. Encrypting system log files automatically
2. Defining reusable configuration templates that can be applied conditionally across multiple hierarchy levels
3. Bypassing syntax verification checks during candidate commits
4. Managing remote cloud database cluster synchronizations

Correct Answer: 2

Explanation

Junos configuration groups allow administrators to define modular, reusable configuration blocks (templates) that can be applied globally or conditionally across specific interfaces, routing protocols, or device models. This eliminates configuration redundancy, simplifies large-scale deployments, and ensures policy consistency across enterprise networking hardware.

Question 269

How do dynamic port profiles function within Mist Wired Assurance?

1. They automatically identify connected device types and apply appropriate VLAN and security policies
2. They lock switch ports into static 10Mbps half-duplex modes
3. They encrypt physical copper cabling paths using pre-shared keys
4. They configure OSPF routing neighbor timer parameters

Correct Answer: 1

Explanation

Mist Wired Assurance leverages dynamic port profiles to automate switch management across campus environments. By recognizing connected endpoint types—such as IP phones, printers, or access points—through telemetry and profiling, the switch dynamically applies the correct VLAN assignments, security policies, and quality of service parameters without manual intervention.

Question 270

Which Junos configuration hierarchy is used to customize and direct system log messages to remote syslog servers?

1. set system syslog
2. set protocols log-server
3. set routing-options forward-log
4. set firewall log-target

Correct Answer: 1

Explanation

In Junos OS, all event logging parameters are configured under the system syslog hierarchy. Administrators can define specific log files, facility severities (such as notice, info, or error), and remote syslog server destination IP addresses, ensuring that critical security and operational events are archived securely off-box.

Question 271

What parameters prevent routing loops within a BGP Route Reflection cluster?

1. AS-Path length metric counters
2. Originator-ID and Cluster-List attributes
3. Multi-Exit Discriminator values
4. Local Preference weights

Correct Answer: 2

Explanation

Because internal BGP disables advertisement between IBGP peers (split-horizon), Route Reflectors are deployed to pass updates. To prevent routing loops within the reflection cluster, two specialized attributes are utilized: the Originator-ID (identifying the router that injected the route into the AS) and the Cluster-List (tracking which route reflector clusters the route has traversed).

Question 272

How does Weighted Round Robin (WRR) scheduling allocate bandwidth among multiple output queues during network congestion?

1. By dropping all packets in low-priority queues immediately
2. By servicing queues in a cyclic manner proportional to their assigned weights
3. By converting packet headers into binary protocol buffer streams
4. By transmitting only real-time voice priority frames

Correct Answer: 2

Explanation

Weighted Round Robin is a common queuing algorithm used in enterprise switches and routers. It services multiple output queues in a cyclic round-robin fashion, allocating transmission opportunities proportional to each queue’s configured weight. This ensures that high-priority queues receive more bandwidth while preventing lower-priority traffic from experiencing total starvation during congestion.

Question 273

What happens when a new member switch with a mismatched Junos software version is added to an active Juniper Virtual Chassis?

1. The entire stack shuts down permanently to prevent corruption
2. The Master routing engine automatically distributes the matching software version to the new member
3. The new switch operates in standalone isolation mode indefinitely
4. All configuration files are erased from internal flash memory

Correct Answer: 2

Explanation

Juniper Virtual Chassis technology simplifies software lifecycle management. When a new member switch joins an active stack running a different Junos version, the Master routing engine detects the version mismatch and automatically pushes the matching software image to the new switch, synchronizing firmware versions across the entire logical stack.

Question 274

Which pipe command modifier in Junos allows an administrator to count the number of lines returned by an operational command output?

1. | count
2. | match
3. | display xml
4. | except

Correct Answer: 1

Explanation

Junos operational commands support powerful output filtering and manipulation pipes. The | count modifier reads the text output of any command, counts the total number of lines returned, and displays the summary integer. This is exceptionally useful when auditing large lists of firewall entries, ARP caches, or BGP route tables.

Question 275

What key capability distinguishes an OSPF Not-So-Stubby Area (NSSA) from a standard Stub Area?

1. Total blocking of all routing information across area boundaries
2. Permission to inject external routes originating within the NSSA via Type 7 LSAs
3. Requirement for full-mesh static IP tunnels between all internal nodes
4. Elimination of all Area Border Routers from the topology design

Correct Answer: 2

Explanation

While a standard OSPF stub area blocks external Type 5 LSAs completely, an NSSA provides a flexible extension that allows external routes to be injected into the area from an internal ASBR. It achieves this using specialized Type 7 LSAs, which the NSSA Area Border Router then translates into standard Type 5 LSAs before propagating them across the rest of the OSPF domain.

Question 276

How does Marvis Actions prioritize network issues for enterprise IT administrators?

1. By generating random support tickets every hour
2. By analyzing scope, impact, and frequency of anomalies to highlight high-priority issues
3. By sorting items purely by switch serial numbers and manufacturing dates
4. By checking physical copper cable color codes in wiring closets

Correct Answer: 2

Explanation

Marvis Actions uses advanced AI and machine learning telemetry correlation to analyze network health. Instead of treating all alerts equally, Marvis evaluates the scope (number of affected users), impact (severity of failure), and frequency of anomalies, intelligently prioritizing critical root causes so IT teams can resolve high-impact issues first.

Question 277

What operational advantage do prefix lists provide over standard route filters in Junos routing policies?

1. They allow modular prefix referencing and easier maintenance within policy definitions
2. They encrypt route updates using pre-shared cryptographic keys
3. They eliminate the need for BGP autonomous system numbers entirely
4. They convert IPv4 network prefixes directly into Layer 2 MAC addresses

Correct Answer: 1

Explanation

Prefix lists in Junos allow administrators to define a named list of IP prefixes once and reference that list across multiple routing policies or firewall filters. If a network prefix changes, the administrator updates the prefix list in a single location rather than editing numerous individual policy terms, greatly reducing administrative overhead and error risks.

Question 278

What two combined parameters constitute the Bridge ID in standard Spanning Tree protocols?

1. Configurable priority value and base MAC address
2. IP address and active subnet mask
3. Autonomous system number and router ID
4. Port index number and VLAN identifier

Correct Answer: 1

Explanation

The Spanning Tree Bridge ID is an 8-byte field that uniquely identifies every bridge in a network. It consists of a 2-byte configurable priority value (usually defaulting to 32768) combined with a 6-byte base MAC address belonging to the switch. The switch with the lowest numerical Bridge ID wins the root bridge election.

Question 279

Which Junos configuration hierarchy defines local user authentication accounts, user classes, and password policies?

1. set system login
2. set security authentication
3. set access control-list
4. set protocols user-auth

Correct Answer: 1

Explanation

All administrative access control settings in Junos OS are managed under the system login hierarchy. Administrators configure local user accounts, assign permission classes (such as super-user, operator, or read-only), set SSH public keys, and enforce password complexity rules within this configuration branch.

Question 280

Which encapsulation protocols are commonly terminated by Mist Edge to extend enterprise campus networks to remote branches?

1. IPsec and GRE
2. OSPF and BGP
3. SNMP and Syslog
4. HTTP and HTTPS

Correct Answer: 1

Explanation

Mist Edge is designed to terminate secure IPsec or GRE tunnels originating from remote access point deployments right back to the central data center or campus edge. This allows organizations to maintain centralized tunneling policies, dynamic VLAN mapping, and secure traffic steering across distributed branch offices.