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

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

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

What does a packet header mainly contain?

  1. AControl information such as source and destination addresses
  2. BThe user's actual file contents, split into equal-sized pieces
  3. CThe website's text and images
  4. DThe cable type used for the link
3.Easy

In networking, a protocol is:

  1. AA set of rules for the format and order of messages
  2. BA program that blocks viruses
  3. CA list of all devices on a network
  4. DA physical cable between two devices
4.Medium

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

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

What does an MX record in DNS specify?

  1. AThe IPv4 address of a web server
  2. BAn alias name for another host
  3. CThe mail servers that accept email for a domain
  4. DThe name servers for a zone
6.Medium

Which of these is a private IPv4 address range?

  1. A8.8.8.0/24
  2. B192.168.0.0/16
  3. C100.0.0.0/8
  4. D200.1.1.0/24
7.Hard

Why does the side that closes a TCP connection first stay in the TIME_WAIT state for twice the maximum segment lifetime?

  1. ATo keep the encryption keys for later reuse
  2. BTo let the routers along the path update their routing tables for the next connection
  3. CSo delayed segments die out and the final ACK can be resent if it was lost
  4. DTo wait for the DNS cache to expire
8.Hard

A DNS cache poisoning attack aims to:

  1. ADelete DNS servers
  2. BSteal Wi-Fi passwords
  3. CMake a resolver store a false IP address for a domain
  4. DOverload a server with traffic so that it stops answering queries

Answer key

  1. 1. B · A hub
  2. 2. A · Control information such as source and destination addresses
  3. 3. A · A set of rules for the format and order of messages
  4. 4. D · Many compromised machines flood a target with traffic
  5. 5. C · The mail servers that accept email for a domain
  6. 6. B · 192.168.0.0/16
  7. 7. C · So delayed segments die out and the final ACK can be resent if it was lost
  8. 8. C · Make a resolver store a false IP address for a domain

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