Configuration Basics

JN0-106 · 35 questions

• A field technician receives a brand-new Juniper router to commission as a POP node for a rural broadband cooperative. Fresh out of the box, the technician logs in over the console as root with no password prompted and tries to commit a change to enable a management IP address, but the commit is rejected. What must be configured first?
• A technician is commissioning a brand-new POP router for a rural fiber build-out, and no IP address has been configured on the management interface yet. Which access method will let the technician log in and configure the device for the first time?
• A co-op network engineer sets 'host-name pop-fiber-042' on a newly commissioned aggregation router. What is the primary effect of this configuration statement?
• A rural broadband cooperative is onboarding a new field technician who needs to run diagnostic commands on POP routers but should never be able to change the configuration. Which approach best reflects Junos login-class design?
• A co-op wants to give a NOC staffer enough access to run day-to-day operational commands — including clearing interface counters during troubleshooting — without granting any configuration rights. Which built-in Junos login class fits this need?
• A cooperative wants POP routers to first try authenticating administrator logins against a central RADIUS server before falling back to any other method. Which Junos configuration concept controls this sequencing?
• A cooperative centralizes administrator authentication through a RADIUS server at its main office, but POP routers in outlying towns sometimes lose connectivity to that office during fiber cuts. What should the authentication-order configuration include to keep local technicians able to log in during an outage?
• A cooperative's security policy requires that administrators never log in directly as root over the network, so every action can be tied to a named account. Which Junos configuration approach enforces this?
• A co-op operates POP routers across several small towns and wants their system clocks to stay tightly synchronized so that log timestamps line up when correlating an outage across multiple sites. Which configuration accomplishes this?
• A cooperative's monitoring platform needs to poll interface statistics from POP routers but should never be able to push configuration changes through SNMP. How should the SNMP community be configured?
• A rural cooperative wants log messages from every POP router forwarded to a central log server at its NOC so technicians don't have to check each device individually after an outage. Which configuration accomplishes this?
• A co-op engineer wants to reference the NTP and syslog servers by hostname instead of by IP address in a POP router's configuration. What must be configured first for hostname references to resolve correctly?
• A cooperative creates a new local user account for a technician on a POP router but forgets to assign a login class before committing. What is the practical consequence?
• A co-op assigns a technician to a custom login class that includes view and network permissions but not configure. What happens when that technician attempts to enter configuration mode on a POP router?
• A technician unboxes a new POP router for a rural fiber build-out and connects only the management interface to a switch port that hands out DHCP leases, without touching the console. What is a technician relying on to get an initial address this way?
• A co-op engineer types the root-authentication plain-text-password command and enters a password at the prompt. What does Junos do with that password in the resulting configuration?
• After a POP router is fully commissioned with a management IP address and SSH enabled, a co-op still keeps a console cable connected to it in the equipment rack. What operational purpose does that console connection continue to serve?
• A cooperative's centralized syslog server is getting flooded with routine informational messages from dozens of POP routers, making real problems hard to spot. How should the syslog configuration on each router be adjusted?
• At a rural fiber cooperative's regional POP, a technician reviewing the aggregation router's interface list sees the name ge-0/0/2. In the Junos physical interface naming convention, what does the "0/0/2" portion identify?
• A field engineer for a rural broadband cooperative is bringing up a new fiber transit uplink. She needs to set the port's link speed and framing, and separately assign an IP address for routing to the upstream carrier. Which pairing correctly matches each property to the level where Junos expects it configured?
• A regional ISP is provisioning a new subscriber VLAN on aggregation port ge-1/0/5. Logical unit 100 needs the address 10.20.30.1/24 so subscriber CPE devices can route through it. Which configuration statement correctly assigns that address?
• A rural ISP's network team configures a stable address on lo0.0 for every core and edge router, and uses that address as the source for routing protocol sessions and remote management. What makes the loopback interface well-suited for that role?
• An engineer is assigning the address on lo0.0 for a POP router that will serve as the router ID and management anchor for that site. Which subnet mask is the correct choice for that loopback address, and why?
• A cooperative's aggregation router has three subscriber ports, ge-0/0/4, ge-0/0/6, and ge-0/0/9, that all need the identical family inet and MTU settings applied at once instead of being configured one interface at a time. Which Junos feature is built for exactly this?
• Inside an interface-range block, an engineer needs to add ge-0/0/10 through ge-0/0/23 as a contiguous block of subscriber ports, separately from a handful of individually named interfaces elsewhere in the network. What is the functional difference between the member and member-range statements available inside that block?
• A rural broadband cooperative operates 40 small POPs, each running an identical block of NTP and syslog configuration on its router. Maintaining that block by hand in 40 separate candidate configurations is error-prone whenever a setting needs to change. What is the Junos-recommended way to keep that shared block consistent across every POP router?
• An engineer wants a configuration group to apply a common MTU setting to every Gigabit Ethernet subscriber port on a router without listing each ge- interface name individually inside the group. How should the group's interface stanza be written to achieve that?
• An engineer defines a group named pop-common under the groups hierarchy with shared NTP and syslog settings, and commits the change. On the router itself, though, neither service reflects any of the new settings. What is the most likely explanation?
• A subscriber aggregation interface inherits an MTU value from a configuration group applied router-wide with apply-groups, but the same interface also has an explicit MTU value configured directly on it. Which value takes effect on that interface?
• A cooperative's compliance policy requires that every committed router configuration be automatically copied off the device to a central archive, without relying on a technician to remember to do it manually. Which Junos feature is designed for this?
• An engineer wants a POP router's configuration to be transferred to the central archive server automatically every time a commit succeeds, rather than only on a fixed periodic schedule. Which statement under the archival configuration hierarchy triggers that commit-driven behavior?
• Ahead of a large maintenance window at a regional POP, an engineer wants to snapshot the currently active, known-good configuration as a dedicated safety net, separate from the router's normal rollback history. Which action accomplishes that?
• A change during a maintenance window breaks IP reachability to a POP router, leaving only console access available. A rescue configuration was saved earlier that day. What is the correct way to restore the router to that known-good baseline?
• An aggregation router administrator numbers each subscriber logical unit to match the VLAN ID it carries, for example unit 210 for VLAN 210, purely to make the configuration easier to read. Which statement about Junos logical unit numbering is accurate?
• An engineer configuring a new transit uplink at a carrier interconnect point sets an encapsulation type on the physical interface, then separately configures VLAN tagging and an IP address on a logical unit beneath it. Which statement correctly describes why these properties are split across those two levels?