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. B161
  3. C53
  4. D80
2.Easy

What is the default port number for SSH?

  1. A22
  2. B23
  3. C53
  4. D110
3.Easy

What does a VPN mainly provide?

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

What does a subnet mask of 255.255.255.0 correspond to in CIDR notation?

  1. A/32
  2. B/16
  3. C/24
  4. D/8
5.Medium

What is the role of a default gateway on a host?

  1. AIt is the DNS server
  2. BIt assigns MAC addresses
  3. CIt is the switch port the host is connected to
  4. DIt is the router used for traffic to other networks
6.Medium

Which subnet mask corresponds to /20?

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

After repeated collisions, classic Ethernet stations choose their waiting time from a range that doubles each time. Why?

  1. ATo lower the chance of colliding again when many stations compete
  2. BTo synchronise all stations to one clock
  3. CTo give the station with the highest MAC address priority on the shared cable
  4. DTo make the cable carry signals further
8.Hard

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

  1. ACompressing the data before encryption
  2. BUsing a longer domain name
  3. CSending the certificate twice
  4. DForward secrecy from ephemeral Diffie-Hellman key exchange

Answer key

  1. 1. C · 53
  2. 2. A · 22
  3. 3. D · An encrypted tunnel across an untrusted network such as the internet
  4. 4. C · /24
  5. 5. D · It is the router used for traffic to other networks
  6. 6. D · 255.255.240.0
  7. 7. A · To lower the chance of colliding again when many stations compete
  8. 8. D · Forward secrecy from ephemeral Diffie-Hellman key exchange

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