Free JN0-106 practice test: 30 questions with answers

Each switch port is its own collision domain, so hosts on different ports do not contend for the medium. Flooding does not merge the ports into one domain, a switch forwards broadcasts rather than blocking them by default, and VLANs create broadcast domains rather than collision domains.

A router does not forward Layer 2 broadcasts from one interface to another, so each router interface begins a new broadcast domain. A switch without VLANs, a repeater, and a hub all forward broadcasts to every other port or segment, so none of them separates broadcast domains by default.

TCP establishes a connection with a three-way handshake and provides acknowledgments and retransmission, while UDP is connectionless and does not by itself guarantee delivery. The other two statements swap the characteristics of the two protocols.

Routers choose the matching route with the longest prefix length, which here is the /24 entry. The /8 and /16 routes also match but are less specific, and table order or learning time does not decide the choice.

A /27 block holds 32 addresses, so this subnet runs from 172.16.5.192 to 172.16.5.223, and the last address in the block is the broadcast. 172.16.5.255 is the broadcast of a /24, while 172.16.5.199 and 172.16.5.207 are ordinary host addresses inside the block.

OSPF hellos are routing protocol packets, which the PFE passes up to the Routing Engine as exception traffic. The PFE may perform the first lookup, but the Routing Engine runs OSPF, and the chassis and management daemons do not process routing protocol hellos.

In Junos the Routing Engine handles control-plane work such as the routing protocols and the routing table, while the Packet Forwarding Engine forwards traffic using the forwarding table derived from it. The other options either swap the two planes' roles or place both planes on the Routing Engine.

Junos forwards transit traffic in the PFE using the forwarding table, so the Routing Engine is not in the per-packet path for transit packets. Exception traffic, such as routing protocol packets and packets addressed to the router, is sent to the Routing Engine, and Gigabit Ethernet interfaces do have hardware forwarding.

rpd is the routing protocol daemon on the Routing Engine that runs the routing protocols and maintains the routing table. chassisd monitors hardware, mgd handles CLI and NETCONF sessions, and the PFE forwards packets rather than running routing protocols.

The lo0 filter is designed to protect the Routing Engine by controlling traffic addressed to the router's own addresses. A routing policy filters routes rather than packets, a higher hello interval does not stop a flood, and a discard default upstream would drop all legitimate traffic too.

The match pipe displays only the lines that contain the given text. except removes the matching lines, count reports how many lines are in the output rather than showing them, and find starts the output at the first match and keeps everything below it.

Junos keeps edits in the candidate configuration until a commit activates them, so the new address is not active yet. save only writes the candidate to a file, rollback 0 discards uncommitted edits, and restarting the Routing Engine is unnecessary.

The compare pipe in configuration mode displays the candidate changes against the active configuration. show system commit lists commit history, run show configuration displays the active configuration, and display set only changes the output format.

J-Web is a browser-based interface for configuration, monitoring, and troubleshooting tasks. Compiling software from source and running routing protocol processes are not J-Web functions, since Junos software is installed from packages and protocols run on the Routing Engine.

The view permission allows show commands for operational state and does not allow changes. all grants every permission, configure allows editing the configuration, and maintenance allows maintenance actions such as reboots.

Configuration groups define statements once under the groups hierarchy, and apply-groups inserts them wherever they are needed. Routing instances, rescue configurations, and VLAN assignments each serve different purposes and are not what groups do.

The rescue configuration is loaded with rollback rescue, and it still has to be committed to become active. Loading the factory default replaces the site's settings, while commit confirmed and a reboot do not load the rescue file.

NTP servers and syslog files are configured under the system hierarchy as system ntp and system syslog. SNMP community strings sit in the top-level snmp hierarchy, and OSPF areas are configured under protocols.

CRC errors usually point to a physical or link-layer problem such as a damaged cable, a faulty optic, or a speed or duplex mismatch. Changing the MTU, adding a static route, or changing the OSPF cost does not fix the underlying error.

monitor interface displays live counters for the named interface and keeps refreshing until stopped. show interfaces terse gives a one-time snapshot, show log messages displays the system log, and request system reboot restarts the device.

request system software rollback sets the previously installed release to load on the next reboot, so a reboot is required afterward. rollback 1 applies to configuration, a plain reboot loads the current release, and show system software only displays information.

Junos root password recovery requires physical access to the console and a reboot into the documented recovery procedure, because remote management needs a valid login. Rollback commands and SNMP do not reset the root password, and devices do not ship with an SSH key that bypasses authentication.

show route forwarding-table displays the forwarding table the PFE uses for lookups. show route displays the full routing table with all candidate routes, show route summary only gives counts, and show configuration routing-options displays configuration rather than routes.

Junos chooses the route with the lowest preference value, and static routes default to 5 while OSPF internal routes default to 10. Metrics are only compared between routes from the same protocol, so the other options are wrong.

A routing instance has its own routing table and protocol context, so overlapping prefixes can coexist on one device. Configuration groups only reuse statements, and firewall filters and prefix lists do not create separate routing tables.

Junos static routes are configured under routing-options static with a prefix and a next-hop address. The protocols hierarchy does not hold static routes, and OSPF or interface address statements do not define a default route.

Export policies control which routes a protocol advertises, so a term matching from protocol static with an accept action, applied as an OSPF export policy, advertises the static routes. Import policies, firewall filters, and interface prefix lists do not make OSPF advertise routes.

Routing policy terms match route attributes such as the originating protocol and the BGP community. Source address and destination port match packet headers, so they belong to firewall filter terms instead.

accept is a terminating action, so the filter stops at the first matching term. count is non-terminating and only records a counter, so the packet is counted and then accepted.

Loose mode only requires that some route to the source exists, which suits asymmetric routing. Strict mode requires the best route to point back out the arrival interface, and the other options check the wrong address or the wrong table.