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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1.Easy

Which device simply repeats every incoming signal out of all its other ports?

  1. AA router
  2. BA switch
  3. CA firewall
  4. DA hub
2.Easy

What is the default port number for HTTPS?

  1. A80
  2. B443
  3. C25
  4. D21
3.Easy

What is the default port number for SSH?

  1. A110
  2. B53
  3. C23
  4. D22
4.Medium

What characterises a distributed denial-of-service (DDoS) attack?

  1. AA virus deletes files on a single PC
  2. BMany compromised machines flood a target with traffic
  3. CAn attacker reads unencrypted Wi-Fi traffic from a nearby car
  4. DOne attacker guesses a user's password
5.Medium

How long does it take to put a 1500-byte packet onto a 12 Mbit/s link (transmission delay)?

  1. A0.125 ms
  2. B12 ms
  3. C8 ms
  4. D1 ms
6.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. A10.1.0.0/16, because it is the longest matching prefix
  2. BBoth routes, splitting the traffic equally
  3. C10.0.0.0/8, because it was added first
  4. D10.0.0.0/8, because it covers more addresses than the /16
7.Hard

In the TCP/IP model, which layer adds port numbers?

  1. AApplication layer
  2. BInternet layer
  3. CTransport layer
  4. DLink layer
8.Hard

Why does IPv6 not need NAT for address shortage?

  1. AIPv6 does not use addresses
  2. BIPv6 encrypts all addresses
  3. CIPv6 only works on local networks, so addresses never need to be shared globally
  4. DIts 128-bit address space is large enough to give every device a global address

Answer key

  1. 1. D · A hub
  2. 2. B · 443
  3. 3. D · 22
  4. 4. B · Many compromised machines flood a target with traffic
  5. 5. D · 1 ms
  6. 6. A · 10.1.0.0/16, because it is the longest matching prefix
  7. 7. C · Transport layer
  8. 8. D · Its 128-bit address space is large enough to give every device a global address

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