JNCIA-JUNOS Practice Test 6 — 10 Questions

Question 1

A network engineer is configuring a new Juniper device. They intend to apply a firewall filter to an interface to only allow SSH traffic from a specific management subnet. Which configuration approach best follows Juniper best practices?

Accepted Answer

Define the filter under 'firewall family inet' and apply it under 'interfaces ge-0/0/0 unit 0 family inet filter input filter-name'. Option A is correct because it follows Juniper best practices by defining the firewall filter under the `firewall family inet` hierarchy (which is the standard location for IPv4 filters) and applying it as an input filter on the physical interface `ge-0/0/0 unit 0 family inet`. This configuration ensures that only SSH traffic from the specified management subnet is permitted inbound on that interface, while all other traffic is dropped by default (since firewall filters in Junos have an implicit deny at the end).

Answer

Define the filter under 'firewall family inet' and apply it under 'interfaces lo0 unit 0 family inet filter input filter-name'

Answer

Define the filter under 'firewall family inet' and apply it under 'interfaces ge-0/0/0 unit 0 family inet input'

Answer

Define the filter under 'firewall family any' and apply it under 'interfaces ge-0/0/0 unit 0 family any filter input'

Question 2

An engineer is designing a network and needs to ensure that management traffic (SSH, SNMP) is always permitted, even if an interface firewall filter is applied. Which Juniper best practice should be followed?

Accepted Answer

Apply a firewall filter on the loopback interface (lo0) to protect the device. Applying a firewall filter to the loopback interface (lo0) is the Juniper best practice for protecting management traffic because the loopback interface is the logical termination point for all control plane traffic, including SSH and SNMP. This ensures that management traffic is always permitted regardless of which physical interface it arrives on, while still allowing interface-specific filters to be applied for data plane traffic without risk of blocking management access.

Answer

Use a firewall filter that permits all management traffic at the top of the list on each interface

Answer

Apply a firewall filter to the management interface (fxp0)

Answer

Disable the firewall filter on all interfaces

Question 3

Which TWO are correct statements about the Junos configuration hierarchy?

Accepted Answer

The 'interfaces' hierarchy is used to configure physical and logical interfaces.. Option B is correct because the 'interfaces' hierarchy in Junos is specifically designed to configure both physical interfaces (e.g., ge-0/0/0) and logical interfaces (e.g., ge-0/0/0.100), including parameters like IP addresses, MTU, and VLAN tagging. This is a fundamental part of Junos configuration, as all network traffic flows through interfaces defined under this hierarchy.

Answer

The 'routing-options' hierarchy is used to configure interface IP addresses.

Answer

Firewall filters are configured under 'policy-options'.

Answer

The 'protocols' hierarchy includes system-level settings like hostname.

Question 4

A junior engineer is asked to change the hostname of a Juniper device from 'Router-1' to 'Core-Router'. Which command sequence correctly commits the change?

Accepted Answer

set system host-name Core-Router; commit. Option A is correct because the Junos CLI uses the 'set system host-name' command (with a hyphen in 'host-name') to change the device hostname, and 'commit' applies the change to the active configuration. The command sequence is syntactically valid and follows Junos configuration hierarchy.

Answer

edit system; set host-name Core-Router; commit

Answer

set system hostname Core-Router; commit

Answer

set system host-name Core-Router; commit

Question 5

A network engineer needs to add an additional IP address to an interface that already has a primary IP configured. Which method should be used?

Accepted Answer

set interfaces ge-0/0/0 unit 0 family inet address 10.0.0.2/24 secondary. Option B is correct because in Junos, to add an additional IP address to an interface that already has a primary IP configured, you must append the 'secondary' keyword to the address configuration statement. This allows multiple IPv4 addresses on the same logical interface unit, with the first address assigned being the primary and subsequent addresses marked as secondary.

Answer

set interfaces ge-0/0/0 unit 0 family inet address 10.0.0.2/24

Answer

set interfaces ge-0/0/0 unit 0 family inet secondary address 10.0.0.2/24

Answer

set interfaces ge-0/0/0 unit 0 family inet address 10.0.0.2/24 primary

Question 6

A network engineer wants to schedule a reboot of a Juniper device at 3:00 AM. Which command should be used?

Accepted Answer

request system reboot at 03:00. Option C is correct because the 'request system reboot at 03:00' command schedules a one-time reboot of the Juniper device at the specified time (3:00 AM). The 'at' parameter allows the engineer to set an absolute time for the reboot, which is the exact requirement for scheduling a reboot at a specific future time.

Answer

request system configuration rescue save

Answer

request system reboot

Answer

load override /config/juniper.conf.gz

Question 7

Which THREE commands are used for operational monitoring of routing protocols?

Accepted Answer

show isis adjacency. The 'show isis adjacency' command is used to verify the state of IS-IS neighbor adjacencies, which is a core operational monitoring task for the IS-IS routing protocol. It displays the interface, neighbor system ID, level, and adjacency state (e.g., Up, Down, Initializing), allowing an engineer to confirm that IS-IS neighbors are properly established.

Answer

show interfaces terse

Answer

show arp

Question 8

During troubleshooting, an engineer notices that BGP sessions are flapping. They suspect that the issue might be related to the maximum number of routes allowed. To see if the BGP import policy is rejecting routes, which operational command would provide immediate insight?

Accepted Answer

show bgp neighbor x.x.x.x. Option D is correct because the 'show bgp neighbor x.x.x.x' command displays detailed BGP session information, including the number of received and accepted routes, as well as any prefix-limit or policy-related rejections. If the BGP import policy is rejecting routes due to exceeding the maximum allowed, this command will show the 'received prefixes' count alongside the 'accepted prefixes' count, immediately revealing if routes are being dropped. This provides direct insight into whether the flapping is caused by route limit enforcement.

Answer

show version

Answer

show interfaces terse

Answer

show route protocol bgp

Question 9

Refer to the exhibit. An engineer has made changes to the candidate configuration. What will happen when the engineer issues the 'commit' command?

Accepted Answer

Both the interface address and security policy will be activated.. Option D is correct because in Junos, the 'commit' command activates all changes in the candidate configuration atomically. Both the interface address change and the security policy will be applied simultaneously after validation. Junos does not require a reboot for security policy changes, and syntax errors cause the commit to fail, not be ignored.

Answer

The commit will succeed but the security policy will be ignored due to a syntax error.

Answer

Only the interface address change will be committed because security policies require a reboot.

Answer

The configuration will be validated; if errors exist, the commit will fail.

Question 10

Refer to the exhibit. An engineer wants to verify that static routes for 10.0.1.0/24 and 10.0.2.0/24 are present in the routing table. Based on the output, which statement is true?

Accepted Answer

Both routes are active and have the same preference value.. The output shows both 10.0.1.0/24 and 10.0.2.0/24 as static routes with a preference of 5. Since the preference value is the same and both are listed as active (the 'A' flag is present in the routing table), both routes are installed and active in the forwarding table. In Junos, a static route's default preference is 5, and any route with a lower preference is preferred; here both have equal preference, so they coexist as active routes.

Answer

Both routes have a preference of 0.

Answer

Only the 10.0.1.0/24 route is active.

Answer

Both routes use the same next-hop IP address.