Cisco Certified Network Associate
(CCNA) Professional Certification Exam
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
1. Which command is used to verify the operational status of interfaces and
display their IP addresses on a Cisco router?
A. show ip interface brief
B. show running-config
C. show ip route
D. show protocols
A. show ip interface brief
Rationale: This command provides a concise, single-line summary of each
interface, including its IP address, status (up/up), and protocol status, making it
the most efficient way to verify interface configuration and connectivity.
2. What is the default administrative distance of an OSPF route?
A. 90
B. 100
C. 110
D. 120
C. 110
,Rationale: Administrative distance represents the trustworthiness of a routing
source. OSPF is assigned a default value of 110, which allows it to be preferred
over RIP (120) but less preferred than EIGRP (90) or static routes (1).
3. Which layer of the OSI model is responsible for logical addressing and
routing?
A. Data Link
B. Network
C. Transport
D. Session
B. Network
Rationale: The Network layer (Layer 3) handles the logical addressing (IP
addresses) of devices and determines the best path for data to travel across
interconnected networks using routers.
4. You need to assign an IP address to a host that allows it to communicate on
the same subnet as 192.168.1.0/26. Which address is valid?
A. 192.168.1.63
B. 192.168.1.64
C. 192.168.1.32
D. 192.168.1.128
C. 192.168.1.32
Rationale: A /26 mask (255.255.255.192) creates subnets with 64 addresses
each. The range for the first subnet is 192.168.1.0 to 192.168.1.63. 192.168.1.32
falls within this usable range.
5. Which command displays the contents of the MAC address table on a Cisco
switch?
A. show mac-address-table
,B. show ip arp
C. show vlan brief
D. show switch port
A. show mac-address-table
Rationale: Switches use the MAC address table (or Content Addressable Memory
- CAM table) to map source MAC addresses to specific physical ports, allowing
the switch to forward frames intelligently.
6. What is the primary function of the ARP protocol?
A. Resolving IP addresses to MAC addresses
B. Resolving MAC addresses to IP addresses
C. Assigning IP addresses to hosts
D. Routing packets between subnets
A. Resolving IP addresses to MAC addresses
Rationale: Address Resolution Protocol (ARP) is used by a device to find the
hardware (MAC) address of a destination node when it only knows the target's
IP address within the local network segment.
7. Which of the following is a private IPv4 address range as defined by RFC
1918?
A. 11.0.0.0/8
B. 172.16.0.0/12
C. 192.0.0.0/24
D. 224.0.0.0/4
B. 172.16.0.0/12
, Rationale: RFC 1918 defines private address spaces: 10.0.0.0/8, 172.16.0.0/12,
and 192.168.0.0/16. These ranges are intended for internal network use and are
not routable on the public internet.
8. What is the purpose of the Native VLAN in an 802.1Q trunk?
A. To carry management traffic
B. To provide redundancy for other VLANs
C. To carry untagged traffic across the trunk link
D. To encrypt data for security
C. To carry untagged traffic across the trunk link
Rationale: In an 802.1Q trunk, the Native VLAN is the VLAN that remains
untagged when traversing the trunk, allowing devices that do not support VLAN
tagging to communicate across the switch infrastructure.
9. Which protocol operates at the Application layer and is used to translate
hostnames into IP addresses?
A. DHCP
B. DNS
C. SNMP
D. HTTP
B. DNS
Rationale: The Domain Name System (DNS) is a distributed database that
converts human-readable domain names (e.g., www.cisco.com) into numerical
IP addresses, which are required for network routing.
10.What is the broadcast address for the subnet 192.168.10.0/28?
A. 192.168.10.15
B. 192.168.10.16
(CCNA) Professional Certification Exam
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
1. Which command is used to verify the operational status of interfaces and
display their IP addresses on a Cisco router?
A. show ip interface brief
B. show running-config
C. show ip route
D. show protocols
A. show ip interface brief
Rationale: This command provides a concise, single-line summary of each
interface, including its IP address, status (up/up), and protocol status, making it
the most efficient way to verify interface configuration and connectivity.
2. What is the default administrative distance of an OSPF route?
A. 90
B. 100
C. 110
D. 120
C. 110
,Rationale: Administrative distance represents the trustworthiness of a routing
source. OSPF is assigned a default value of 110, which allows it to be preferred
over RIP (120) but less preferred than EIGRP (90) or static routes (1).
3. Which layer of the OSI model is responsible for logical addressing and
routing?
A. Data Link
B. Network
C. Transport
D. Session
B. Network
Rationale: The Network layer (Layer 3) handles the logical addressing (IP
addresses) of devices and determines the best path for data to travel across
interconnected networks using routers.
4. You need to assign an IP address to a host that allows it to communicate on
the same subnet as 192.168.1.0/26. Which address is valid?
A. 192.168.1.63
B. 192.168.1.64
C. 192.168.1.32
D. 192.168.1.128
C. 192.168.1.32
Rationale: A /26 mask (255.255.255.192) creates subnets with 64 addresses
each. The range for the first subnet is 192.168.1.0 to 192.168.1.63. 192.168.1.32
falls within this usable range.
5. Which command displays the contents of the MAC address table on a Cisco
switch?
A. show mac-address-table
,B. show ip arp
C. show vlan brief
D. show switch port
A. show mac-address-table
Rationale: Switches use the MAC address table (or Content Addressable Memory
- CAM table) to map source MAC addresses to specific physical ports, allowing
the switch to forward frames intelligently.
6. What is the primary function of the ARP protocol?
A. Resolving IP addresses to MAC addresses
B. Resolving MAC addresses to IP addresses
C. Assigning IP addresses to hosts
D. Routing packets between subnets
A. Resolving IP addresses to MAC addresses
Rationale: Address Resolution Protocol (ARP) is used by a device to find the
hardware (MAC) address of a destination node when it only knows the target's
IP address within the local network segment.
7. Which of the following is a private IPv4 address range as defined by RFC
1918?
A. 11.0.0.0/8
B. 172.16.0.0/12
C. 192.0.0.0/24
D. 224.0.0.0/4
B. 172.16.0.0/12
, Rationale: RFC 1918 defines private address spaces: 10.0.0.0/8, 172.16.0.0/12,
and 192.168.0.0/16. These ranges are intended for internal network use and are
not routable on the public internet.
8. What is the purpose of the Native VLAN in an 802.1Q trunk?
A. To carry management traffic
B. To provide redundancy for other VLANs
C. To carry untagged traffic across the trunk link
D. To encrypt data for security
C. To carry untagged traffic across the trunk link
Rationale: In an 802.1Q trunk, the Native VLAN is the VLAN that remains
untagged when traversing the trunk, allowing devices that do not support VLAN
tagging to communicate across the switch infrastructure.
9. Which protocol operates at the Application layer and is used to translate
hostnames into IP addresses?
A. DHCP
B. DNS
C. SNMP
D. HTTP
B. DNS
Rationale: The Domain Name System (DNS) is a distributed database that
converts human-readable domain names (e.g., www.cisco.com) into numerical
IP addresses, which are required for network routing.
10.What is the broadcast address for the subnet 192.168.10.0/28?
A. 192.168.10.15
B. 192.168.10.16
