Computer networks worksheet with answers

Free printable Computer networks worksheet: 8 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy

What is the main job of a firewall?

  1. ATo convert domain names into addresses
  2. BTo speed up downloads by caching files
  3. CTo assign IP addresses to hosts
  4. DTo allow or block traffic according to security rules
2.Easy

What does a VPN mainly provide?

  1. AAutomatic backup of files to a server
  2. BA faster physical connection to the internet through a dedicated line
  3. CA free public IP address for every device
  4. DAn encrypted tunnel across an untrusted network such as the internet
3.Easy

How is an IPv6 address usually written?

  1. AFour decimal numbers separated by dots
  2. BSixteen decimal numbers separated by dots
  3. CEight groups of four hexadecimal digits separated by colons
  4. DSix pairs of hexadecimal digits separated by dashes or colons
4.Medium

Why is UDP often preferred for live video calls?

  1. ALow delay matters more than retransmitting every lost packet
  2. BUDP encrypts data automatically
  3. CUDP is required for all video
  4. DUDP guarantees every packet arrives, so the picture never freezes
5.Medium

A router has routes for 10.0.0.0/8 and 10.1.0.0/16. Which route does it use for a packet to 10.1.5.5?

  1. ABoth routes, splitting the traffic equally
  2. B10.0.0.0/8, because it was added first
  3. C10.1.0.0/16, because it is the longest matching prefix
  4. D10.0.0.0/8, because it covers more addresses than the /16
6.Medium

What is the main purpose of a VLAN?

  1. ATo give each device a public IP address
  2. BTo split one physical switched network into separate broadcast domains
  3. CTo increase the speed of every switch port
  4. DTo encrypt all traffic between switches so other departments cannot read it
7.Hard

How does a content delivery network (CDN) mainly improve web performance?

  1. AIt serves cached content from servers close to the users
  2. BIt replaces TCP with a faster transport protocol
  3. CIt removes the need for DNS lookups
  4. DIt increases the bandwidth of the users' own home connections
8.Hard

An attacker on a LAN sends forged ARP replies claiming the gateway's IP address. What is the likely result?

  1. AVictims send traffic for the gateway to the attacker, enabling a man-in-the-middle attack
  2. BAll DNS queries fail across the internet
  3. CThe gateway's IP address is permanently changed to the attacker's address on every router
  4. DThe switch shuts down all of its ports

Answer key

  1. 1. D · To allow or block traffic according to security rules
  2. 2. D · An encrypted tunnel across an untrusted network such as the internet
  3. 3. C · Eight groups of four hexadecimal digits separated by colons
  4. 4. A · Low delay matters more than retransmitting every lost packet
  5. 5. C · 10.1.0.0/16, because it is the longest matching prefix
  6. 6. B · To split one physical switched network into separate broadcast domains
  7. 7. A · It serves cached content from servers close to the users
  8. 8. A · Victims send traffic for the gateway to the attacker, enabling a man-in-the-middle attack

Full step-by-step solutions: practise this topic on examproblems.com.