CCNA v2.0 practice exam: 10 free questions, every option explained

A server is being added to 192.168.4.0/23. Which address can be assigned to it?

• A192.168.4.255
  Correct. 192.168.4.0/23 spans 192.168.4.0 to 192.168.5.255. Usable hosts run from 192.168.4.1 to 192.168.5.254, so 192.168.4.255 is a normal host address in the middle of the range.
• B192.168.6.1
  192.168.6.0 starts the next /23 block, outside this subnet.
• C192.168.5.255
  That is the broadcast address of 192.168.4.0/23.
• D192.168.4.0
  That is the network address of the subnet.

Match each prefix to its number of usable host addresses: 1) /26, 2) /28, 3) /30.

• A1 30, 2 6, 3 2
  These are the values for /27, /29 and /30.
• B1 64, 2 16, 3 4
  These are total addresses; network and broadcast must be subtracted.
• C1 126, 2 30, 3 6
  These are the values for /25, /27 and /29.
• D1 62, 2 14, 3 2
  Correct. /26 = 2^6 - 2 = 62; /28 = 2^4 - 2 = 14; /30 = 2^2 - 2 = 2.

An engineer must validate a campus cabling diagram. Which order of steps is BEST?

• ACollect CDP/LLDP neighbors, compare ports to the diagram, trace mismatches, update the diagram
  Correct. Gather live neighbor data, compare it with the documentation, investigate differences on site, then correct the records.
• BTrace mismatches, collect CDP/LLDP neighbors, update the diagram, compare ports to the diagram
  Mismatches cannot be traced before the data is compared.
• CCompare ports to the diagram, update the diagram, collect CDP/LLDP neighbors, trace mismatches
  There is nothing to compare until neighbor data is collected.
• DUpdate the diagram, collect CDP/LLDP neighbors, trace mismatches, compare ports to the diagram
  Editing the diagram before collecting data records guesses, not facts.

Which statement about PortFast on a Catalyst switch running Rapid PVST+ is correct?

• AThe port becomes the root port immediately after link-up
  PortFast does not affect the root election.
• BSpanning tree is disabled on the port and BPDUs are ignored
  STP remains active; a received BPDU still changes the port's behavior.
• CIt still sends BPDUs and runs STP; it only skips the discarding and learning wait
  Correct. PortFast changes the port to an edge port; STP is not disabled and BPDUs are still sent.
• DThe port stops sending and receiving BPDUs once PortFast is enabled
  That is BPDU filter, not PortFast.

Which TWO ports are appropriate for PortFast? (Choose TWO.)

• AAn access port serving a desktop PC
  Correct. A single host never sends BPDUs.
• BA port to an unmanaged hub with several devices
  A hub could later carry a switch and create a loop.
• CAn access port serving a network printer
  Correct. A printer is an end host.
• DA port in an EtherChannel to another switch
  Switch-to-switch bundles must run normal STP.
• EAn uplink to the distribution switch
  A switch link must participate in the normal topology.

Which statement about the OSPF router ID is true?

• AIt is a 32-bit value written in dotted decimal and does not need to be a reachable address
  Correct. The router ID is an identifier, not an address; 9.9.9.9 is valid even if no interface carries it.
• BIt is changed automatically when a higher loopback address is added
  Once chosen, the ID stays until the process restarts, even if a higher address appears.
• CIt must be the IP address of the interface facing the neighbor
  The ID is per process, not per interface, and need not be assigned to any interface.
• DIt must be identical on all routers in the area
  Router IDs must be unique; a duplicate blocks adjacencies.

Match each routing table code to its meaning: 1 S*, 2 O E2, 3 L.

• A1 static candidate default, 2 OSPF external type 2, 3 local interface address
  Correct. S* is a static route flagged as candidate default; O E2 is an OSPF external type 2 route; L is the router's own address as a host route.
• B1 static candidate default, 2 OSPF inter-area route, 3 local interface address
  Inter-area OSPF routes are coded O IA; E2 means external type 2.
• C1 static route via Null0, 2 OSPF external type 2, 3 local interface address
  The asterisk marks a candidate default route, not a discard route.
• D1 static candidate default, 2 OSPF external type 2, 3 neighbor learned by LLDP
  L in the routing table means local, the router's own address; LLDP adds no routes.

Which sequence describes how IOS XE evaluates a packet against an inbound IPv4 ACL?

• ACompare every line, act on the most specific match, permit the packet if nothing matches
  IOS XE does not look for the most specific line, and the default is deny.
• BCompare lines top-down, act on the first match and stop, drop if nothing matches
  Correct. ACLs use first-match logic and end with an implicit deny.
• CCompare lines top-down, act on the last match, drop the packet if nothing matches
  Processing stops at the first match.
• DCompare lines bottom-up, act on the first match, drop the packet if nothing matches
  Evaluation starts at the lowest sequence number.

Which sequence describes how a site-to-site IPsec tunnel comes up on IOS XE?

• AInteresting traffic, IKE phase 1 (IKE SA), IKE phase 2 (IPsec SAs), data protected by ESP
  Correct. Traffic that matches the policy triggers IKE; phase 1 builds a secure channel, phase 2 negotiates the IPsec SAs, then data flows under ESP.
• BIKE phase 2 (IPsec SAs), IKE phase 1 (IKE SA), interesting traffic, data protected by ESP
  Phase 2 is negotiated inside the channel that phase 1 builds, so it cannot come first.
• CIKE phase 1 (IKE SA), data protected by ESP, IKE phase 2 (IPsec SAs), interesting traffic
  ESP needs the IPsec SAs from phase 2 first.
• DInteresting traffic, data protected by ESP, IKE phase 1 (IKE SA), IKE phase 2 (IPsec SAs)
  Data cannot be protected before the SAs that hold the keys exist.

Match each syslog severity level number to its name: 1 = level 1, 2 = level 3, 3 = level 6. Which mapping is correct?

• A1 critical, 2 errors, 3 notifications
  Critical is level 2 and notifications is level 5.
• B1 alerts, 2 warnings, 3 debugging
  Warnings is level 4 and debugging is level 7.
• C1 emergencies, 2 errors, 3 informational
  Emergencies is level 0, not level 1.
• D1 alerts, 2 errors, 3 informational
  Correct. 0 emergencies, 1 alerts, 2 critical, 3 errors, 4 warnings, 5 notifications, 6 informational, 7 debugging.