CISCO CERTIFICATION EXAMS 2026–2027
COMPREHENSIVE STUDY GUIDE With
Networking Practice Questions, Lab Review &
Certification Prep
Question 1
Which of the following best describes the primary function of a router in a
network?
A. Forwarding traffic based on MAC addresses within the same network
segment
B. Forwarding traffic between different networks based on IP addresses
C. Filtering traffic based on application-layer data
D. Assigning IP addresses to devices on the network
Correct Answer: B
Rationale: A router's primary function is to forward traffic between
different networks using IP addresses to make forwarding
decisions. Option A describes a switch (Layer 2 forwarding based on MAC
addresses). Option C describes a firewall or next-generation firewall
(NGFW). Option D describes a DHCP server.
Question 2
A network administrator is troubleshooting connectivity issues and needs to
determine the path packets take from a source to a destination. Which
command should the administrator use?
A. ping
B. traceroute
,C. ipconfig
D. arp
Correct Answer: B
Rationale: The traceroute (or tracert on Windows) command displays
the path packets take from source to destination, showing each hop along
the route. Option A — ping tests basic connectivity but does not show the
path. Option C — ipconfig displays IP configuration on a Windows
host. Option D — arp displays the ARP table.
Question 3
Which of the following protocols operates at the Transport Layer (Layer 4) of
the OSI model and provides reliable, connection-oriented communication?
A. UDP
B. TCP
C. IP
D. ICMP
Correct Answer: B
Rationale: TCP (Transmission Control Protocol) operates at Layer 4 and
provides reliable, connection-oriented communication with features like
sequencing, acknowledgments, and retransmission. Option A — UDP is also
Layer 4 but provides connectionless, unreliable communication. Option C —
IP operates at Layer 3 (Network Layer). Option D — ICMP operates at Layer
3.
Question 4
What is the decimal equivalent of the binary number 11001010?
A. 128
B. 192
,C. 202
D. 210
Correct Answer: C
Rationale: 11001010₂ = 1×128 + 1×64 + 0×32 + 0×16 + 1×8 + 0×4 + 1×2 +
0×1 = 128 + 64 + 8 + 2 = 202. Option A (128) is 10000000. Option B (192) is
11000000. Option D (210) is 11010010.
Question 5
A network uses the subnet mask 255.255.255.0. How many usable host
addresses are available in each subnet?
A. 254
B. 255
C. 256
D. 512
Correct Answer: A
Rationale: A /24 subnet mask (255.255.255.0) provides 2⁸ = 256 total
addresses. The network address and broadcast address are unusable,
leaving 254 usable host addresses. Option B (255) is incorrect — the
network and broadcast addresses are subtracted. Option C (256) is the total
addresses, not usable. Option D (512) is for a /23 subnet.
Question 6
Which of the following TCP/IP model layers corresponds to the OSI model's
Network Layer?
A. Application Layer
B. Transport Layer
C. Internet Layer
D. Network Access Layer
, Correct Answer: C
Rationale: The Internet Layer of the TCP/IP model corresponds to the
OSI Network Layer (Layer 3). Option A — Application Layer corresponds to
OSI Layers 5–7. Option B — Transport Layer corresponds to OSI Layer
4. Option D — Network Access Layer corresponds to OSI Layers 1–2.
Question 7
What is the purpose of the ARP protocol?
A. To resolve IP addresses to MAC addresses
B. To resolve MAC addresses to IP addresses
C. To assign IP addresses dynamically
D. To route packets between networks
Correct Answer: A
Rationale: ARP (Address Resolution Protocol) resolves IP addresses to
MAC addresses so that devices can communicate on the same local network
segment. Option B — Reverse ARP (RARP) resolves MAC addresses to IP
addresses. Option C — DHCP assigns IP addresses dynamically. Option D —
Routing is performed by routers.
Question 8
Which IPv6 address type is equivalent to a broadcast address in IPv4?
A. Unicast
B. Multicast
C. Anycast
D. IPv6 does not have broadcast addresses
Correct Answer: D
COMPREHENSIVE STUDY GUIDE With
Networking Practice Questions, Lab Review &
Certification Prep
Question 1
Which of the following best describes the primary function of a router in a
network?
A. Forwarding traffic based on MAC addresses within the same network
segment
B. Forwarding traffic between different networks based on IP addresses
C. Filtering traffic based on application-layer data
D. Assigning IP addresses to devices on the network
Correct Answer: B
Rationale: A router's primary function is to forward traffic between
different networks using IP addresses to make forwarding
decisions. Option A describes a switch (Layer 2 forwarding based on MAC
addresses). Option C describes a firewall or next-generation firewall
(NGFW). Option D describes a DHCP server.
Question 2
A network administrator is troubleshooting connectivity issues and needs to
determine the path packets take from a source to a destination. Which
command should the administrator use?
A. ping
B. traceroute
,C. ipconfig
D. arp
Correct Answer: B
Rationale: The traceroute (or tracert on Windows) command displays
the path packets take from source to destination, showing each hop along
the route. Option A — ping tests basic connectivity but does not show the
path. Option C — ipconfig displays IP configuration on a Windows
host. Option D — arp displays the ARP table.
Question 3
Which of the following protocols operates at the Transport Layer (Layer 4) of
the OSI model and provides reliable, connection-oriented communication?
A. UDP
B. TCP
C. IP
D. ICMP
Correct Answer: B
Rationale: TCP (Transmission Control Protocol) operates at Layer 4 and
provides reliable, connection-oriented communication with features like
sequencing, acknowledgments, and retransmission. Option A — UDP is also
Layer 4 but provides connectionless, unreliable communication. Option C —
IP operates at Layer 3 (Network Layer). Option D — ICMP operates at Layer
3.
Question 4
What is the decimal equivalent of the binary number 11001010?
A. 128
B. 192
,C. 202
D. 210
Correct Answer: C
Rationale: 11001010₂ = 1×128 + 1×64 + 0×32 + 0×16 + 1×8 + 0×4 + 1×2 +
0×1 = 128 + 64 + 8 + 2 = 202. Option A (128) is 10000000. Option B (192) is
11000000. Option D (210) is 11010010.
Question 5
A network uses the subnet mask 255.255.255.0. How many usable host
addresses are available in each subnet?
A. 254
B. 255
C. 256
D. 512
Correct Answer: A
Rationale: A /24 subnet mask (255.255.255.0) provides 2⁸ = 256 total
addresses. The network address and broadcast address are unusable,
leaving 254 usable host addresses. Option B (255) is incorrect — the
network and broadcast addresses are subtracted. Option C (256) is the total
addresses, not usable. Option D (512) is for a /23 subnet.
Question 6
Which of the following TCP/IP model layers corresponds to the OSI model's
Network Layer?
A. Application Layer
B. Transport Layer
C. Internet Layer
D. Network Access Layer
, Correct Answer: C
Rationale: The Internet Layer of the TCP/IP model corresponds to the
OSI Network Layer (Layer 3). Option A — Application Layer corresponds to
OSI Layers 5–7. Option B — Transport Layer corresponds to OSI Layer
4. Option D — Network Access Layer corresponds to OSI Layers 1–2.
Question 7
What is the purpose of the ARP protocol?
A. To resolve IP addresses to MAC addresses
B. To resolve MAC addresses to IP addresses
C. To assign IP addresses dynamically
D. To route packets between networks
Correct Answer: A
Rationale: ARP (Address Resolution Protocol) resolves IP addresses to
MAC addresses so that devices can communicate on the same local network
segment. Option B — Reverse ARP (RARP) resolves MAC addresses to IP
addresses. Option C — DHCP assigns IP addresses dynamically. Option D —
Routing is performed by routers.
Question 8
Which IPv6 address type is equivalent to a broadcast address in IPv4?
A. Unicast
B. Multicast
C. Anycast
D. IPv6 does not have broadcast addresses
Correct Answer: D
