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 SSH?

  1. A110
  2. B23
  3. C22
  4. D53
2.Easy

Which application protocol transfers files using separate control and data connections?

  1. AHTTP
  2. BFTP
  3. CDNS
  4. DSMTP
3.Easy

What does DNS do?

  1. AAssigns IP addresses to devices automatically
  2. BEncrypts web traffic
  3. CTranslates domain names into IP addresses
  4. DRoutes packets between networks
4.Medium

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

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

Which medium access method did classic shared (half-duplex) Ethernet use?

  1. ACSMA/CA
  2. BCSMA/CD
  3. CToken passing
  4. DTDMA
6.Medium

Which subnet mask corresponds to /20?

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

You must divide 192.168.1.0/24 into at least 5 subnets with up to 25 hosts each. Which prefix length fits best?

  1. A/26
  2. B/25
  3. C/27
  4. D/28
8.Hard

With sliding-window protocols, how does Go-Back-N differ from Selective Repeat after one frame is lost?

  1. AGo-Back-N resends the lost frame and all later ones; Selective Repeat only the lost one
  2. BBoth resend the whole window from the start
  3. CNeither ever resends lost frames
  4. DGo-Back-N resends only the lost frame; Selective Repeat resends that frame and all later ones

Answer key

  1. 1. C · 22
  2. 2. B · FTP
  3. 3. C · Translates domain names into IP addresses
  4. 4. A · With cookies holding a session identifier or token
  5. 5. B · CSMA/CD
  6. 6. B · 255.255.240.0
  7. 7. C · /27
  8. 8. A · Go-Back-N resends the lost frame and all later ones; Selective Repeat only the lost one

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