Networking
23 free questions with worked answers, and 635 more in the full bank.
Free questions
What device is commonly used to connect multiple computers within a LAN?
1 mark · Easy
Which cable type is most commonly used for Ethernet connections?
1 mark · Easy
What is the purpose of DNS?
1 mark · Easy
Which of the following tools is used to diagnose network connectivity issues?
1 mark · Easy
What does VPN stand for?
1 mark · Easy
What is the primary function of a router?
4 marks · Hard
What protocol is used to send email?
4 marks · Hard
A user reports that they are unable to access the hospital management system due to a firewall blocking the connection. What should you do to resolve this issue?
4 marks · Hard
A junior admin is looking at a packet capture and notices MAC addresses are being used to forward frames. Which OSI layer is responsible for this activity?
1 mark · Easy
While investigating a slow application, you observe TCP window size zero messages in Wireshark. At what layer of the OSI model does this flow control issue reside?
3 marks · Medium
Users report that their web browsers are failing to negotiate TLS encryption with a newly deployed internal server. Which OSI layer is failing to establish this secure connection?
4 marks · Hard
An engineer connects a spectrum analyzer to a coax cable to check for electromagnetic interference. What OSI layer is being analyzed?
1 mark · Easy
A routing loop has caused TTL values to expire, dropping IP packets. In which OSI layer does the TTL field exist?
3 marks · Medium
During a network outage, a technician finds that a fiber optic cable was accidentally severed. Which layer of the OSI model is directly impacted by this physical break?
1 mark · Easy
An application requires persistent connections and checkpointing during a large file transfer so it can resume if interrupted. Which OSI layer provides these dialog control features?
4 marks · Hard
You are troubleshooting an IPsec VPN tunnel where ESP packets are being dropped by an intermediary firewall. Which OSI layer protocols are being blocked?
3 marks · Medium
A user complains that they cannot access a specific internal webpage, receiving an HTTP 500 error. At what OSI layer is this error generated?
1 mark · Easy
A switch receives a frame with a destination MAC address of FF:FF:FF:FF:FF:FF. Which OSI layer is responsible for flooding this frame out all ports?
3 marks · Medium
A small office connects all their computers to a single central switch. What physical topology is in use?
1 mark · Easy
An enterprise connects its 5 branch offices directly to every other branch office using point-to-point links for maximum redundancy. What topology does this represent?
3 marks · Medium
A legacy industrial control system uses a single coaxial cable that loops through each machine on the factory floor. If a break occurs, the entire segment fails. What topology is described?
4 marks · Hard
A campus network consists of several star-topology building networks connected together via a high-speed fiber backbone ring. Which term best describes this overall design?
1 mark · Easy
To save costs, a regional ISP connects its routers in a circle, where each router only links to its two nearest neighbors. What topology is deployed?
3 marks · Medium
More Networking questions (page 7 of 11)
Answers and explanations are in the full bank.
- An engineer writes a firewall rule to allow OSPF between two routers and opens a TCP port for it, but the routers still do not form a neighbour relationship. Why? · 3 marks
- Which of the following works at the application layer of the TCP/IP model? · 1 mark
- A database on a remote server accepts connections only from that server itself, and only SSH is open to it. How can an administrator use a graphical database tool on their own laptop to reach it securely? · 3 marks
- Which layer of the OSI model handles logical (IP) addressing and choosing a path between networks? · 1 mark
- A switch delivers frames to the right port by reading their MAC addresses. At which OSI layer does it mainly work? · 1 mark
- A technician finds that a network cable under a desk has been crushed by a chair, and the PC has no link light. At which OSI layer is this fault? · 1 mark
- What is the unit of data called at the data link layer? · 2 marks
- An old hub in a school computer lab is replaced with a switch. What improves? · 1 mark
- How does a switch build its MAC address table? · 2 marks
- Which device connects a district office's local network to its internet provider and forwards packets between the two networks using IP addresses? · 1 mark
- A router has three LAN interfaces, each connected to its own switch with twenty PCs, and no VLANs are configured. How many broadcast domains are there? · 3 marks
- What does a wireless access point do in an office network? · 1 mark
- In a sector office, every PC and printer is cabled to one central switch. What happens if that switch fails? · 2 marks
- A bank wants a full-mesh WAN in which each of its 5 regional sites has a direct link to every other site. How many links are needed? · 3 marks
- A network that links a university's campuses across the city of Kigali, larger than a LAN but smaller than a national WAN, is called a: · 1 mark
- A MAC address is written as 00:1A:2B:3C:4D:5E. What do its first three bytes (00:1A:2B) identify? · 2 marks
- What is the standard maximum payload size (MTU) of an Ethernet frame? · 1 mark
- A server's link to a switch is very slow. The switch port shows many late collisions and CRC errors; the server is set to 100 Mbps full duplex while the switch port is on auto-negotiate. What is the likely problem? · 3 marks
- Access points are being installed on the ceilings of a hospital ward where there are no power sockets. How can they be powered? · 2 marks
- What is the maximum length of a single twisted-pair (Cat5e or Cat6) Ethernet cable run between a switch and a device? · 1 mark
- Which type of cable is normally used to connect a desktop PC to a switch port? · 1 mark
- When terminating a cable to the T568B standard, which wire goes on pin 1? · 2 marks
- Two buildings of a TVET school are 350 metres apart, and the cable route passes a workshop full of heavy electrical machines. What is the best medium for the link? · 2 marks
- A dedicated fibre link of 15 km must connect two district offices. Which type of fibre is appropriate? · 2 marks
- Compared with 2.4 GHz, what is the main trade-off of using the 5 GHz Wi-Fi band in an office? · 2 marks
- Three access points covering neighbouring classrooms all use the 2.4 GHz band. Which set of channels avoids overlap between them? · 3 marks
- Which IEEE standard is marketed as Wi-Fi 6? · 1 mark
- Why is WPA3-Personal more secure than WPA2-Personal for an office Wi-Fi network that uses a shared password? · 2 marks
- How many bits make up an IPv4 address? · 1 mark
- Which of these addresses is a private (RFC 1918) address that cannot be routed on the public internet? · 2 marks
- A technician pings 127.0.0.1 on a PC and gets replies. What does this prove? · 1 mark
- A PC at a district office can print to the printer on its own subnet and open shared folders on a local server, but cannot reach any website or remote office, even by IP address. Which setting is most likely wrong? · 2 marks
- Which dotted-decimal subnet mask is written as /24 in CIDR notation? · 1 mark
- An engineer is told to use a /27 subnet. What is its subnet mask? · 2 marks
- How many usable host addresses does a /26 subnet provide? · 2 marks
- A host is configured as 192.168.10.77 with mask 255.255.255.192. What is the network address of its subnet? · 3 marks
- What is the broadcast address of the subnet that contains 10.4.9.130/25? · 3 marks
- A new floor of a ministry building needs one subnet for 100 computers. Which is the smallest prefix that fits them? · 3 marks
- Two PCs are configured as 10.10.10.14/28 and 10.10.10.18/28. Can they communicate directly without a router? · 3 marks
- A /24 network is divided into /27 subnets. How many subnets does this create? · 2 marks
- An access list must match every address in the subnet 192.168.20.16/28. Which wildcard mask is used? · 3 marks
- Windows shows “another device on the network is using your PC's IP address” on a new staff laptop. The laptop has a static address that falls inside the DHCP scope. What is the proper fix? · 2 marks
- A small business in Rubavu gets a 4G router whose WAN address is 100.72.18.4. The owner sets up port forwarding for a CCTV recorder, but it still cannot be reached from outside. Why? · 3 marks
- How is an IPv6 address normally written? · 1 mark
- What is the shortest correct way to write the IPv6 address 2001:0db8:0000:0000:0000:0000:0000:0001? · 2 marks
- Every IPv6-enabled interface on a network has an address beginning with fe80::, even without any configuration. What kind of address is it? · 2 marks
- The ISP assigns a university an IPv6 prefix beginning with 2001:. What type of IPv6 address is this? · 2 marks
- On a new IPv6 network, laptops obtain working global addresses although no DHCPv6 server exists. How? · 3 marks
- During its move to IPv6, a ministry configures its servers and PCs to run IPv4 and IPv6 side by side, using whichever the other end supports. What is this approach called? · 2 marks
- Which pair of Windows commands makes a PC give up its current DHCP address and request a new one? · 1 mark
- A website moved to a new server an hour ago. Every PC in the office opens the new site except one, which keeps reaching the old server even after restarting the browser. Which command should be run on that PC? · 2 marks
- Under the old classful addressing system, which class does the address 200.10.5.1 belong to? · 1 mark
- A PC is configured with IP 192.168.5.20, mask 255.255.255.0 and default gateway 192.168.6.1. What is wrong with this configuration? · 3 marks
- A district office wants the finance team's PCs kept in a separate broadcast domain from the public reception PCs, although all are plugged into the same switch. What should be configured? · 1 mark
- The link between two switches must carry traffic for the staff, voice and guest VLANs. How is this link configured? · 2 marks
- Two switches report a “native VLAN mismatch” on the trunk between them: one side uses VLAN 1 and the other VLAN 99 as native. What is the risk? · 3 marks
- After VLANs are created, PCs in the finance VLAN can no longer reach the file server in the servers VLAN. What is needed for them to communicate? · 2 marks
- A switch port that connects a single staff PC should be configured as which type of port? · 1 mark
- Two switches in a school are connected by two cables for redundancy. Which protocol stops the extra link from creating an endless loop of broadcasts? · 2 marks
- The network of a district hospital went down when someone connected a small switch to a wall socket in a waiting room. Which protection shuts a user-facing port as soon as another switch appears on it? · 3 marks