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

What is the default port number for DNS?

  1. A67
  2. B80
  3. C161
  4. D53
2.Easy

Which application protocol is used to request web pages from a web server?

  1. AARP
  2. BSMTP
  3. CSNMP
  4. DHTTP
3.Easy

What is the default port number for SSH?

  1. A22
  2. B110
  3. C53
  4. D23
4.Medium

HTTP is stateless. How do websites usually keep a user logged in across requests?

  1. ABy giving each user a fixed IP address
  2. BBy keeping the TCP connection open for days
  3. CBy storing the password in the URL
  4. DWith cookies holding a session identifier or token
5.Medium

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

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

What is a cyclic redundancy check (CRC) used for in Ethernet frames?

  1. ACorrecting every bit error automatically
  2. BEncrypting the frame
  3. CDetecting transmission errors
  4. DChoosing the best route
7.Hard

Which of these addresses is a public (not RFC 1918 private) IPv4 address?

  1. A10.255.0.1
  2. B172.32.0.1
  3. C172.31.0.1
  4. D192.168.255.1
8.Hard

A server's private key is stolen a year from now. Which TLS property keeps today's recorded sessions safe?

  1. ASending the certificate twice
  2. BForward secrecy from ephemeral Diffie-Hellman key exchange
  3. CUsing a longer domain name
  4. DCompressing the data before encryption

Answer key

  1. 1. D · 53
  2. 2. D · HTTP
  3. 3. A · 22
  4. 4. D · With cookies holding a session identifier or token
  5. 5. B · Many compromised machines flood a target with traffic
  6. 6. C · Detecting transmission errors
  7. 7. B · 172.32.0.1
  8. 8. B · Forward secrecy from ephemeral Diffie-Hellman key exchange

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