Cisco CCNA Practice Test 5 — Questions and Answers
Question 1: Which protocol does OSPF use to send routing updates?
- TCP port 89
- UDP port 520
- IP protocol 89 (multicast) (Correct answer)
- ICMP
Correct answer: IP protocol 89 (multicast)
OSPF uses IP protocol number 89 and sends updates via multicast addresses 224.0.0.5 and 224.0.0.6, not TCP or UDP.
Question 2: What is the function of the Spanning Tree Protocol (STP) root bridge?
- It is the switch with the highest MAC address
- It serves as the logical center of the spanning tree topology (Correct answer)
- It blocks all redundant ports in the network
- It forwards traffic only to VLAN 1
Correct answer: It serves as the logical center of the spanning tree topology
The root bridge is elected as the logical center of the STP topology and all path cost calculations are made relative to it.
Question 3: Which access list statement permits all IP traffic from the 10.0.0.0/8 network?
- permit ip 10.0.0.0 0.0.0.255 any
- permit ip 10.0.0.0 255.0.0.0 any
- permit ip 10.0.0.0 0.255.255.255 any (Correct answer)
- permit ip any 10.0.0.0 0.255.255.255
Correct answer: permit ip 10.0.0.0 0.255.255.255 any
The wildcard mask for a /8 network is 0.255.255.255, meaning any address starting with 10 is matched.
Question 4: Which command configures an interface as a VLAN trunk using IEEE 802.1Q encapsulation?
- switchport mode trunk
- switchport trunk encapsulation dot1q (Correct answer)
- switchport access vlan trunk
- trunk mode dot1q enable
Correct answer: switchport trunk encapsulation dot1q
The 'switchport trunk encapsulation dot1q' command must be issued before setting the port to trunk mode on some Cisco platforms.
Question 5: What is a characteristic of a full-mesh WAN topology?
- Each site connects only to a central hub
- Every site has a direct connection to every other site (Correct answer)
- Sites connect in a ring pattern
- Only two sites are directly connected
Correct answer: Every site has a direct connection to every other site
In a full-mesh topology, every site has a direct point-to-point connection to every other site, providing maximum redundancy.
Question 6: Which IPv6 transition mechanism encapsulates IPv6 packets within IPv4 packets?
- Dual stack
- NAT64
- Tunneling (Correct answer)
- 6to4 translation
Correct answer: Tunneling
IPv6 tunneling encapsulates IPv6 packets inside IPv4 headers so they can traverse IPv4-only networks.
Question 7: A switch port is in the 'err-disabled' state. What is the most likely cause?
- The connected device is powered off
- A security violation such as port security was triggered (Correct answer)
- The VLAN assigned to the port does not exist
- STP placed the port in blocking state
Correct answer: A security violation such as port security was triggered
The err-disabled state is commonly triggered by port security violations, BPDU guard activation, or other security events.
Cisco CCNA Practice Test 5
Which protocol does OSPF use to send routing updates?