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.

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Name: ____________________   Date: ____________

1.Easy

How many layers does the OSI reference model have?

  1. A7
  2. B9
  3. C5
  4. D4
2.Easy

What is the main job of a firewall?

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

What is the default port number for HTTPS?

  1. A443
  2. B80
  3. C21
  4. D25
4.Medium

A browser receives HTTP status code 404. What does it mean?

  1. AThe server had an internal error
  2. BThe requested resource was not found
  3. CThe client must log in first
  4. DThe request succeeded
5.Medium

A signal travels 2000 km through fibre at about 2 × 10⁸ m/s. What is the propagation delay?

  1. A0.1 ms
  2. B100 ms
  3. C1 ms
  4. D10 ms
6.Medium

Which subnet mask corresponds to /20?

  1. A255.255.255.240
  2. B255.255.248.0
  3. C255.255.240.0
  4. D255.255.224.0
7.Hard

How does fragmentation differ in IPv6 compared with IPv4?

  1. AIPv6 fragments at the transport layer inside TCP
  2. BIPv6 does not allow packets larger than 576 bytes
  3. CIPv6 routers fragment every packet larger than 64 bytes before forwarding it on the path
  4. DRouters never fragment IPv6 packets; only the source can, using path MTU discovery
8.Hard

A student runs a game server on a PC behind a home NAT router. Friends on the internet cannot connect. What is the usual fix?

  1. AGive the PC a different MAC address so the router can find it from outside
  2. BConfigure port forwarding on the router to the PC's private address
  3. CChange the PC's subnet mask to /32
  4. DTurn off the PC's DNS client

Answer key

  1. 1. A · 7
  2. 2. D · To allow or block traffic according to security rules
  3. 3. A · 443
  4. 4. B · The requested resource was not found
  5. 5. D · 10 ms
  6. 6. C · 255.255.240.0
  7. 7. D · Routers never fragment IPv6 packets; only the source can, using path MTU discovery
  8. 8. B · Configure port forwarding on the router to the PC's private address

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