JNCIA Juniper Networks Certified Internet Associate Exam — Questions and Answers

Question 1: What should you do when troubleshooting a network configuration issue?

Immediately restart all systems
Make random changes until the problem goes away
Follow a systematic approach: identify, research, test, implement, verify (Correct answer)
Escalate everything without investigation

Correct answer: Follow a systematic approach: identify, research, test, implement, verify

A systematic troubleshooting approach ensures the root cause is identified and the fix is verified without creating new issues.

Question 2: What does the 'show chassis hardware' command display in Junos?

Physical hardware inventory including FPCs, PICs, Routing Engines, and serial numbers (Correct answer)
Current interface error counters
Power supply and fan status
Software version and installed packages

Correct answer: Physical hardware inventory including FPCs, PICs, Routing Engines, and serial numbers

'show chassis hardware' provides a complete inventory of all installed hardware components with their descriptions, part numbers, and serial numbers, useful for inventory and RMA purposes.

Question 3: How should VLAN IDs be planned when deploying Juniper EX switches in a multi-switch environment?

Assign random VLAN IDs per switch since VLANs are locally significant
Assign unique VLAN IDs consistently across all switches and trunk ports to ensure traffic segmentation and correct tagging (Correct answer)
Use VLAN IDs above 4000 to avoid conflicts
Only configure VLANs on the core switch

Correct answer: Assign unique VLAN IDs consistently across all switches and trunk ports to ensure traffic segmentation and correct tagging

VLAN IDs must be consistently planned across the network because 802.1Q VLAN tags are significant end-to-end on trunk ports. Inconsistent VLAN IDs cause traffic misclassification.

Question 4: In a dual-RE Junos chassis, what is the function of the backup Routing Engine?

Actively forwards packets alongside the primary RE
Monitors system temperature and fans
Stores backup configuration files only
Maintains a synchronized copy of the routing state and can take over as master if the primary RE fails (Correct answer)

Correct answer: Maintains a synchronized copy of the routing state and can take over as master if the primary RE fails

The backup RE stays synchronized with the primary RE via GRES and NSR, allowing near-instantaneous RE failover without disrupting protocol adjacencies or active sessions.

Question 5: Which command applies a firewall filter to an interface in the input direction?

set interfaces ge-0/0/0 unit 0 family inet filter input FILTER-NAME (Correct answer)
set interfaces ge-0/0/0 filter input FILTER-NAME
set firewall filter FILTER-NAME apply-to ge-0/0/0
apply filter FILTER-NAME to ge-0/0/0 input

Correct answer: set interfaces ge-0/0/0 unit 0 family inet filter input FILTER-NAME

Firewall filters are applied to logical interfaces under the protocol family. The correct syntax is 'set interfaces [if] unit [n] family inet filter input [name]'.

Question 6: What type of routing protocol is OSPF?

Link-State Interior Gateway Protocol (Correct answer)
Path-Vector Exterior Gateway Protocol
Hybrid Exterior Gateway Protocol
Distance-Vector Interior Gateway Protocol

Correct answer: Link-State Interior Gateway Protocol

OSPF (Open Shortest Path First) is a link-state IGP that builds a complete topology map of the network using LSAs and calculates the shortest path using Dijkstra's SPF algorithm.

Question 7: What is the 'inet.3' routing table used for in Junos MPLS?

Stores multicast MPLS routes
Is the backup routing table for inet.0
Stores MPLS-resolved next-hops for BGP routes, allowing BGP to use MPLS LSPs as next-hops for traffic forwarding over the MPLS backbone (Correct answer)
Stores all IPv4 routes including MPLS labels

Correct answer: Stores MPLS-resolved next-hops for BGP routes, allowing BGP to use MPLS LSPs as next-hops for traffic forwarding over the MPLS backbone

inet.3 contains MPLS tunnel next-hops (RSVP-TE LSPs and LDP LSPs). BGP references inet.3 to resolve next-hops through MPLS tunnels, allowing BGP routes to be forwarded using MPLS LSPs rather than direct IP routing.

Question 8: What is the best practice for monitoring troubleshooting methods systems?

Implement automated monitoring with alerting thresholds (Correct answer)
Check systems manually once a month
Rely on vendor notifications exclusively
Monitor only when users report problems

Correct answer: Implement automated monitoring with alerting thresholds

Automated monitoring with properly configured alerting thresholds enables proactive identification and resolution of issues.

Question 9: What is the best practice for monitoring security fundamentals systems?

Implement automated monitoring with alerting thresholds (Correct answer)
Check systems manually once a month
Monitor only when users report problems
Rely on vendor notifications exclusively

Correct answer: Implement automated monitoring with alerting thresholds

Automated monitoring with properly configured alerting thresholds enables proactive identification and resolution of issues.

Question 10: What is the best practice for monitoring compliance standards systems?

Implement automated monitoring with alerting thresholds (Correct answer)
Check systems manually once a month
Rely on vendor notifications exclusively
Monitor only when users report problems

Correct answer: Implement automated monitoring with alerting thresholds

Automated monitoring with properly configured alerting thresholds enables proactive identification and resolution of issues.

Question 11: What is the best practice for monitoring network configuration systems?

Rely on vendor notifications exclusively
Implement automated monitoring with alerting thresholds (Correct answer)
Check systems manually once a month
Monitor only when users report problems

Correct answer: Implement automated monitoring with alerting thresholds

Automated monitoring with properly configured alerting thresholds enables proactive identification and resolution of issues.

Question 12: What is the BGP attribute 'LOCAL_PREF' used for?

To define the AS path length for external BGP routes
To set the weight of a BGP route for inbound traffic
To influence outbound routing decisions within an AS by preferring routes with higher LOCAL_PREF values (Correct answer)
To configure the BGP community for route filtering

Correct answer: To influence outbound routing decisions within an AS by preferring routes with higher LOCAL_PREF values

LOCAL_PREF is a BGP well-known discretionary attribute shared among iBGP peers within the same AS. Higher LOCAL_PREF values are preferred, influencing which exit point is used for outbound traffic.

Question 13: What does the term "default gateway" refer to?

The router that connects a local network to external networks (Correct answer)
A secondary IP address
The network firewall
The main DNS server

Correct answer: The router that connects a local network to external networks

The default gateway is used to send traffic from a local network to destinations outside the local subnet.

Question 14: How does Junos implement MPLS traffic engineering (TE)?

Using RSVP-TE to signal LSPs with explicit routes and bandwidth reservations, with OSPF or IS-IS TE extensions advertising link bandwidth (Correct answer)
Using BGP to distribute MPLS labels with bandwidth constraints
Traffic engineering is handled automatically by LDP
Through static MPLS label assignments with manual path configuration

Correct answer: Using RSVP-TE to signal LSPs with explicit routes and bandwidth reservations, with OSPF or IS-IS TE extensions advertising link bandwidth

Junos MPLS TE uses RSVP-TE for LSP signaling with constraint-based routing. OSPF-TE or IS-IS-TE extensions flood link attributes (bandwidth, TE metric, SRLG) that CSPF uses to compute explicit paths.

Question 15: Which component in CoS is responsible for marking packets for priority handling?

Forwarder
Policers
Classifier (Correct answer)
Scheduler

Correct answer: Classifier

Classifiers identify packets and assign them to specific forwarding classes based on criteria like IP precedence or DSCP values.

Question 16: What security consideration is most important in network configuration?

Using a single strong password for all systems
Security is not relevant to this area
Disabling logging to improve performance
Implementing the principle of least privilege and defense in depth (Correct answer)

Correct answer: Implementing the principle of least privilege and defense in depth

The principle of least privilege combined with defense in depth provides layered security that protects against various attack vectors.

Question 17: Which Junos feature allows multiple configuration changes to be grouped and committed together?

Rescue configuration
Commit scripts
Candidate configuration (Correct answer)
Event policies

Correct answer: Candidate configuration

The candidate configuration allows operators to stage multiple changes simultaneously. All edits are held in a candidate configuration until a 'commit' is issued, applying them atomically.

Question 18: What is the purpose of a 'pre-check' before implementing Junos configuration changes?

Disabling monitoring during the change window
Rebooting the device to clear stale state
Collecting baseline state (interface status, BGP summary, OSPF neighbors, route table) to compare against post-change state for rapid issue detection (Correct answer)
Pre-approving the change with all stakeholders

Correct answer: Collecting baseline state (interface status, BGP summary, OSPF neighbors, route table) to compare against post-change state for rapid issue detection

A pre-check captures the current operational state of the network before changes, enabling direct comparison with post-change state to quickly identify any unintended impacts.

Question 19: What is the fundamental principle behind security fundamentals in the context of Juniper Networks Certified Internet Associate?

Using the most expensive solutions available
Maximizing system complexity
Avoiding all system changes
Ensuring reliability, security, and optimal performance (Correct answer)

Correct answer: Ensuring reliability, security, and optimal performance

Security Fundamentals in Juniper Networks Certified Internet Associate fundamentally aims to ensure system reliability, security, and optimal performance.

Question 20: How does Junos OS ensure software modularity and fault isolation?

By running all functions in a single monolithic kernel process
By virtualizing the OS for each interface
By running each major function as a separate process (daemon) that can restart independently without affecting others (Correct answer)
By using separate hardware for each routing protocol

Correct answer: By running each major function as a separate process (daemon) that can restart independently without affecting others

Junos OS uses a microkernel architecture where separate daemons handle routing, management, chassis, SNMP, and other functions. A daemon crash only affects that function, not the entire system.

Question 21: In Junos, what is the purpose of a routing policy 'term' order?

All terms are evaluated and the best match wins
Terms are evaluated in order from first to last; the first matching term's action is applied and evaluation stops (Correct answer)
Terms are evaluated alphabetically
Term order only matters for BGP, not OSPF

Correct answer: Terms are evaluated in order from first to last; the first matching term's action is applied and evaluation stops

In Junos routing policies, terms are evaluated sequentially. The first term that matches all conditions executes its action and stops further evaluation, making term order critical to policy correctness.

Question 22: In a Junos firewall filter term, which keyword introduces the match conditions for the term?

then
from (Correct answer)
match
apply

Correct answer: from

The 'from' clause in a Junos firewall filter term defines the match conditions that a packet must satisfy for the term's actions to be applied.

Question 23: What is the fundamental principle behind troubleshooting methods in the context of Juniper Networks Certified Internet Associate?

Maximizing system complexity
Ensuring reliability, security, and optimal performance (Correct answer)
Avoiding all system changes
Using the most expensive solutions available

Correct answer: Ensuring reliability, security, and optimal performance

Troubleshooting Methods in Juniper Networks Certified Internet Associate fundamentally aims to ensure system reliability, security, and optimal performance.

Question 24: What is the primary purpose of a Junos firewall filter?

To load balance traffic
To encrypt traffic between interfaces
To perform NAT translation
To match packets and apply actions such as accept, discard, or reject (Correct answer)

Correct answer: To match packets and apply actions such as accept, discard, or reject

Junos firewall filters (stateless ACLs) use match conditions and actions to control packet forwarding. They operate at line rate and can accept, discard, reject, or count packets.

Question 25: In Junos BGP, what does the 'export' policy control?

Which BGP routes are accepted from peers
The BGP session establishment parameters
The BGP local preference value
Which routes from the local routing table are advertised to BGP peers (Correct answer)

Correct answer: Which routes from the local routing table are advertised to BGP peers

The BGP 'export' policy in Junos controls which routes from the local RIB are redistributed into BGP and advertised to peers. Without an export policy, only BGP-learned routes are re-advertised.

Question 26: In Junos, what command enables OSPF on an interface?

enable ospf interface ge-0/0/0.0 area 0
set protocols ospf area 0.0.0.0 interface ge-0/0/0.0 (Correct answer)
set interfaces ge-0/0/0 ospf area 0
set ospf enable interface ge-0/0/0

Correct answer: set protocols ospf area 0.0.0.0 interface ge-0/0/0.0

In Junos, OSPF interfaces are configured by adding them to an OSPF area under the protocols hierarchy: 'set protocols ospf area [area-id] interface [interface]'.

Question 27: What is the significance of the 'inet.0' routing table in Junos?

It contains only BGP routes
It is the IPv6 routing table
It is the main IPv4 unicast routing table used for unicast forwarding decisions (Correct answer)
It stores only static routes

Correct answer: It is the main IPv4 unicast routing table used for unicast forwarding decisions

inet.0 is the default IPv4 unicast routing table in Junos. All IPv4 unicast routing protocols (OSPF, BGP, static, connected) install routes here for forwarding decisions.

Question 28: What is the purpose of the Junos CoS 'shaping-rate' parameter in a scheduler?

To define the minimum guaranteed bandwidth for a queue
To set the transmission priority relative to other queues
To configure the buffer size for the queue
To enforce an upper limit on the transmission rate of a queue, preventing it from consuming more than its allocated bandwidth even when other queues are idle (Correct answer)

Correct answer: To enforce an upper limit on the transmission rate of a queue, preventing it from consuming more than its allocated bandwidth even when other queues are idle

The 'shaping-rate' in a Junos scheduler sets the maximum bandwidth a queue can use. Unlike 'transmit-rate' (which is a minimum guarantee), shaping-rate creates a hard ceiling regardless of available capacity.

Question 29: Which command in Junos shows the status of all BGP peers?

show bgp summary (Correct answer)
show bgp neighbors
display bgp peers
show protocols bgp

Correct answer: show bgp summary

'show bgp summary' provides a concise table of all BGP neighbors with their state (Established, Active, Idle), received prefixes, and uptime — the fastest way to assess BGP health.

Question 30: In Junos SRX, what is a security zone?

A physical network segment
A VLAN configuration
A logical grouping of interfaces that share the same security requirements and trust level (Correct answer)
A routing instance

Correct answer: A logical grouping of interfaces that share the same security requirements and trust level

A security zone in Junos SRX is a logical grouping of one or more interfaces that share a common security policy. Traffic between zones is controlled by security policies.

Question 31: What should you do when troubleshooting a system architecture issue?

Make random changes until the problem goes away
Immediately restart all systems
Follow a systematic approach: identify, research, test, implement, verify (Correct answer)
Escalate everything without investigation

Correct answer: Follow a systematic approach: identify, research, test, implement, verify

A systematic troubleshooting approach ensures the root cause is identified and the fix is verified without creating new issues.

Question 32: How do you verify that a firewall filter is working correctly in Junos?

show interfaces and look for filter errors
restart firewall and test connectivity
debug firewall FILTER-NAME
show firewall filter FILTER-NAME and show firewall log to check counter increments and logged packets (Correct answer)

Correct answer: show firewall filter FILTER-NAME and show firewall log to check counter increments and logged packets

Verifying a firewall filter involves checking 'show firewall filter [name]' for term counter increments and 'show firewall log' for packets matched by terms with the 'log' action.

Question 33: In Junos, what does 'set interfaces ge-0/0/0 unit 0 family inet address 192.168.1.1/24' accomplish?

Creates a loopback with IP 192.168.1.1
Sets the interface description
Configures a static route via ge-0/0/0
Assigns IPv4 address 192.168.1.1/24 to logical unit 0 of physical interface ge-0/0/0 (Correct answer)

Correct answer: Assigns IPv4 address 192.168.1.1/24 to logical unit 0 of physical interface ge-0/0/0

This Junos configuration command assigns an IPv4 address to the logical interface unit 0 under the physical Gigabit Ethernet interface ge-0/0/0.

Question 34: What is the fundamental principle behind implementation planning in the context of Juniper Networks Certified Internet Associate?

Avoiding all system changes
Maximizing system complexity
Ensuring reliability, security, and optimal performance (Correct answer)
Using the most expensive solutions available

Correct answer: Ensuring reliability, security, and optimal performance

Implementation Planning in Juniper Networks Certified Internet Associate fundamentally aims to ensure system reliability, security, and optimal performance.

Question 35: Which approach is recommended for implementing data management changes?

Implementing changes only during peak hours
Following a structured change management process with testing (Correct answer)
Skipping documentation to save time
Making all changes at once without testing

Correct answer: Following a structured change management process with testing

A structured change management process with proper testing minimizes risk and ensures successful implementation.

Question 36: How should you document system architecture configurations?

Document only when asked by management
Store documentation on individual workstations
Maintain up-to-date documentation in a centralized, accessible location (Correct answer)
Keep all configuration details in personal memory

Correct answer: Maintain up-to-date documentation in a centralized, accessible location

Centralized, accessible, and current documentation is essential for troubleshooting, disaster recovery, and knowledge sharing.

Question 37: In Junos, what is the maximum number of rollback configurations stored by default?

100
5
50 (Correct answer)
10

Correct answer: 50

Junos stores up to 50 rollback configuration files (rollback 0 through rollback 49), with rollback 0 being the current active configuration and rollback 1 being the previous.

Question 38: Which Junos CLI command displays the current routing table?

show bgp summary
show interfaces
show ospf neighbor
show route (Correct answer)

Correct answer: show route

The 'show route' command displays the routing table in Junos OS, showing all routes learned via static, connected, and dynamic protocols.

Question 39: What is the Junos command to view detailed BGP route information including all path attributes?

show route [prefix] detail (Correct answer)
display bgp path [prefix]
show bgp route [prefix] attributes
show route bgp detail [prefix]

Correct answer: show route [prefix] detail

'show route [prefix] detail' in Junos displays detailed route information including all BGP attributes: AS path, communities, LOCAL_PREF, MED, ORIGIN, and next-hop.

Question 40: What is the primary purpose of a network implementation plan for a Junos deployment?

To configure routing protocols automatically
To document IP addressing only
To document the configuration steps, rollback procedures, and testing criteria before making changes to production (Correct answer)
To purchase hardware from Juniper

Correct answer: To document the configuration steps, rollback procedures, and testing criteria before making changes to production

An implementation plan defines the sequence of configuration changes, pre/post-change verification steps, rollback procedures, and success criteria to reduce risk during network changes.

Question 41: What is the Junos command to verify an LDP-signaled MPLS LSP end-to-end?

traceroute mpls ldp [prefix]
show ldp path [prefix]
ping mpls ldp fec [prefix/len] ttl 255 (Correct answer)
debug ldp lsp [prefix]

Correct answer: ping mpls ldp fec [prefix/len] ttl 255

'ping mpls ldp fec [prefix/length]' sends MPLS ping probes along the LDP LSP for the specified FEC, verifying end-to-end LSP connectivity and data-plane forwarding.

Question 42: What security consideration is most important in troubleshooting methods?

Security is not relevant to this area
Disabling logging to improve performance
Using a single strong password for all systems
Implementing the principle of least privilege and defense in depth (Correct answer)

Correct answer: Implementing the principle of least privilege and defense in depth

The principle of least privilege combined with defense in depth provides layered security that protects against various attack vectors.

Question 43: Which Junos command saves the current configuration to a file for backup?

backup configuration [filename]
copy configuration [filename]
export configuration [filename]
save [filename] (Correct answer)

Correct answer: save [filename]

In Junos configuration mode, the 'save [filename]' command writes the current candidate configuration to a file in the /var/home/[user]/ directory or a specified path.

Question 44: In Junos L3VPN, what is the function of a Route Target (RT)?

Specifies the MPLS label value for the VPN
Controls which VRFs import which VPNv4 routes, implementing the VPN topology (full-mesh, hub-spoke, extranet) (Correct answer)
Sets the routing metric within the VPN
Uniquely identifies each VPN route in the global BGP table

Correct answer: Controls which VRFs import which VPNv4 routes, implementing the VPN topology (full-mesh, hub-spoke, extranet)

Route Targets are BGP extended communities that control VRF route import and export. A VRF exports routes with certain RT values; other VRFs import routes matching specific RT values, defining VPN connectivity topology.

Question 45: Which Junos platform is specifically designed for service provider edge routing with carrier-grade scalability?

EX Series
QFX Series
SRX Series
MX Series (Correct answer)

Correct answer: MX Series

The MX Series is Juniper's Universal Edge Router platform designed for service provider applications, supporting massive scale for BGP, MPLS, L2/L3 VPNs, and subscriber management.

Question 46: What is the default preference value for OSPF routes in Junos?

100 (Correct answer)
200
10
150

Correct answer: 100

In Junos OS, OSPF internal routes have a default preference value of 10, while OSPF external routes have a preference of 150.

Question 47: In Junos, what command shows the MPLS label forwarding table?

show forwarding-table mpls
show mpls labels
show label-table
show route table mpls.0 (Correct answer)

Correct answer: show route table mpls.0

'show route table mpls.0' displays the MPLS label table (mpls.0 routing table) showing incoming labels, operations (pop/swap/push), and next-hops for each MPLS label binding.

Question 48: Which Junos CLI command correctly applies a firewall filter in the inbound direction on a logical interface?

set interfaces ge-0/0/0 unit 0 family inet filter input <filter-name> (Correct answer)
set policy-options policy-statement <filter-name> apply ge-0/0/0
set interfaces ge-0/0/0 firewall-filter <filter-name> direction input
set firewall filter <filter-name> apply interface ge-0/0/0 input

Correct answer: set interfaces ge-0/0/0 unit 0 family inet filter input <filter-name>

Firewall filters are applied under the interface's logical unit and address family using the 'filter input' or 'filter output' knob.

Question 49: What security consideration is most important in implementation planning?

Security is not relevant to this area
Implementing the principle of least privilege and defense in depth (Correct answer)
Disabling logging to improve performance
Using a single strong password for all systems

Correct answer: Implementing the principle of least privilege and defense in depth

The principle of least privilege combined with defense in depth provides layered security that protects against various attack vectors.

Question 50: What does the Packet Forwarding Engine (PFE) do in Junos?

Manages the candidate configuration
Forwards transit packets at line rate using the forwarding table programmed by the Routing Engine (Correct answer)
Runs routing protocols
Handles system login and authentication

Correct answer: Forwards transit packets at line rate using the forwarding table programmed by the Routing Engine

The PFE is the data plane component that performs high-speed packet forwarding using Application-Specific Integrated Circuits (ASICs), using the FIB programmed by the Routing Engine.

Question 51: What Junos process is responsible for managing routing protocols?

rpd (Routing Protocol Daemon) (Correct answer)
mgd (Management Daemon)
pfed (Packet Forwarding Engine Daemon)
chassisd (Chassis Daemon)

Correct answer: rpd (Routing Protocol Daemon)

The Routing Protocol Daemon (rpd) is the primary process managing all routing protocols including OSPF, IS-IS, BGP, RIP, LDP, RSVP, and PIM in Junos OS.

Question 52: What is a Route Distinguisher (RD) in the context of Junos L3VPN?

A security token for VPN authentication
A 64-bit value prepended to customer IPv4 prefixes to create unique VPNv4 routes in MP-BGP, allowing the same IP prefix to exist in multiple VRFs (Correct answer)
A routing metric used to prefer one VPN path over another
A tag that identifies the service provider's AS

Correct answer: A 64-bit value prepended to customer IPv4 prefixes to create unique VPNv4 routes in MP-BGP, allowing the same IP prefix to exist in multiple VRFs

The Route Distinguisher makes customer IPv4 routes globally unique in the BGP table. The same prefix (e.g., 10.0.0.0/8) can exist in multiple customer VRFs without conflict because each VRF has a different RD prepended.

Question 53: How should you document troubleshooting methods configurations?

Keep all configuration details in personal memory
Maintain up-to-date documentation in a centralized, accessible location (Correct answer)
Store documentation on individual workstations
Document only when asked by management

Correct answer: Maintain up-to-date documentation in a centralized, accessible location

Centralized, accessible, and current documentation is essential for troubleshooting, disaster recovery, and knowledge sharing.

Question 54: What should you do when troubleshooting a implementation planning issue?

Follow a systematic approach: identify, research, test, implement, verify (Correct answer)
Immediately restart all systems
Make random changes until the problem goes away
Escalate everything without investigation

Correct answer: Follow a systematic approach: identify, research, test, implement, verify

A systematic troubleshooting approach ensures the root cause is identified and the fix is verified without creating new issues.

Question 55: What are the two main operational modes in the Junos OS CLI?

User and Privileged modes
Operational and Configuration modes (Correct answer)
Admin and Debugging modes
Monitoring and Management modes

Correct answer: Operational and Configuration modes

The Junos OS CLI operates in operational mode for viewing system status and configuration mode for making changes to the system.

Question 56: In OSPF, what is the role of the Area Border Router (ABR)?

Connects two or more OSPF areas and summarizes LSAs between them, reducing LSDB size in non-backbone areas (Correct answer)
Forwards data traffic between areas
Connects the OSPF domain to external routing domains
Performs DR/BDR election for multiple areas

Correct answer: Connects two or more OSPF areas and summarizes LSAs between them, reducing LSDB size in non-backbone areas

An ABR sits at the boundary between OSPF areas. It maintains separate LSDBs for each connected area and generates Summary LSAs (Type 3) to advertise inter-area routes between areas.

Question 57: How should you document security fundamentals configurations?

Document only when asked by management
Maintain up-to-date documentation in a centralized, accessible location (Correct answer)
Store documentation on individual workstations
Keep all configuration details in personal memory

Correct answer: Maintain up-to-date documentation in a centralized, accessible location

Centralized, accessible, and current documentation is essential for troubleshooting, disaster recovery, and knowledge sharing.

Question 58: Which Junos feature prevents IP spoofing by verifying packets arrive on the expected interface?

Firewall filter ingress checking
Source NAT
Dynamic ARP inspection
Unicast Reverse Path Forwarding (uRPF) (Correct answer)

Correct answer: Unicast Reverse Path Forwarding (uRPF)

uRPF checks that a packet's source address would be reachable via the same interface it arrived on (strict mode) or via any interface (loose mode), discarding packets that fail this check.

Question 59: What is 'inter-AS VPN' (Option B) in Junos L3VPN?

A VPN that connects sites in different countries
Inter-AS VPN where full MPLS LSPs span across AS boundaries
A Juniper-proprietary method for multi-AS L3VPN
A method where ASBR routers exchange VPN routes using MP-eBGP, with each ASBR acting as a next-hop change point and allocating new MPLS labels for VPN routes crossing AS boundaries (Correct answer)

Correct answer: A method where ASBR routers exchange VPN routes using MP-eBGP, with each ASBR acting as a next-hop change point and allocating new MPLS labels for VPN routes crossing AS boundaries

Inter-AS VPN Option B (RFC 4364 section 10) uses ASBR-to-ASBR MP-eBGP to exchange labeled VPNv4 routes. Each ASBR changes the next-hop to itself and allocates new labels, enabling L3VPN across multiple autonomous systems without requiring LSPs that span ASes.

Question 60: What security consideration is most important in security fundamentals?

Security is not relevant to this area
Implementing the principle of least privilege and defense in depth (Correct answer)
Using a single strong password for all systems
Disabling logging to improve performance

Correct answer: Implementing the principle of least privilege and defense in depth

The principle of least privilege combined with defense in depth provides layered security that protects against various attack vectors.

Question 61: Which command in Junos operational mode clears OSPF neighbor adjacencies?

clear ospf neighbor all (Correct answer)
flush ospf neighbor
reset ospf neighbors
delete ospf adjacency

Correct answer: clear ospf neighbor all

The 'clear ospf neighbor all' command in Junos operational mode resets all OSPF neighbor adjacencies, forcing OSPF to re-establish neighbors and rebuild the LSDB.

Question 62: Which approach is recommended for implementing troubleshooting methods changes?

Implementing changes only during peak hours
Skipping documentation to save time
Following a structured change management process with testing (Correct answer)
Making all changes at once without testing

Correct answer: Following a structured change management process with testing

A structured change management process with proper testing minimizes risk and ensures successful implementation.

Question 63: What is the purpose of OSPF 'passive' interface configuration in Junos?

Disables OSPF completely on the interface
Advertises the connected subnet into OSPF without sending or receiving OSPF hellos, preventing neighbor formation (Correct answer)
Enables OSPF authentication on the interface
Forces the interface to be elected DR

Correct answer: Advertises the connected subnet into OSPF without sending or receiving OSPF hellos, preventing neighbor formation

A passive OSPF interface advertises its connected subnet into the OSPF domain (via a stub link LSA) but does not send or receive OSPF Hello packets, preventing the formation of OSPF neighbors on that segment.

Question 64: In Junos L3VPN, what is the purpose of the 'vrf-table-label' command?

Configures MPLS on CE-facing interfaces
Allocates a unique MPLS label per VRF routing table to enable MPLS-based forwarding for traffic arriving from the MPLS core toward CE devices (Correct answer)
Creates a label for each route in the VRF
Enables inter-VRF route leaking

Correct answer: Allocates a unique MPLS label per VRF routing table to enable MPLS-based forwarding for traffic arriving from the MPLS core toward CE devices

'vrf-table-label' in Junos allocates a per-VRF MPLS label that the egress PE uses to identify which VRF should receive incoming labeled traffic, enabling correct VPN traffic separation at the PE.

JNCIA Juniper Networks Certified Internet Associate Exam

The JNCIA Juniper Networks Certified Internet Associate Exam validates foundational Junos networking knowledge including system architecture, security fundamentals, network configuration, troubleshooting methods, implementation planning, routing protocols, class of service, and MPLS/VPNs.

Questions

90 min

Time Limit

70%

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These practice questions were written with AI tools. They are not real exam questions. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

Sources & references

Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

learningportal.juniper.net — Test delivery, eligibility, exam format, score release, time limit, exam information · verified Nov 2026
juniper.net — Passing score, score validity, renewal · verified Oct 2026