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Stuff Every IT Tech Should Know

Study for the CompTIA A+ Core 1 and Core 2 exams: hardware, networking, Windows, security and troubleshooting.

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  1. Which TCP port does Secure Shell (SSH) use by default?
    Show the answer

    22. SSH is registered to port 22. Telnet sits on 23 and Remote Desktop on 3389. All three are remote access tools, so techs mix them up.

  2. Which port does SMTP use by default to send and relay email?
    Show the answer

    25. SMTP (Simple Mail Transfer) is registered to port 25. POP3 uses 110 and IMAP uses 143, and both of those are for picking up mail, not sending it.

  3. Which port does POP3 use by default to download email?
    Show the answer

    110. POP3 (Post Office Protocol 3) is registered to port 110. IMAP is 143 and SMTP is 25. POP3 pulls mail down to your device.

All 100 practice questions

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  1. Which TCP port does Secure Shell (SSH) use by default?
  2. Which port does SMTP use by default to send and relay email?
  3. Which port does POP3 use by default to download email?
  4. Which email retrieval protocol uses port 143 by default?
  5. Which port number does DNS use?
  6. In Microsoft's Teams call-quality guide, what does high jitter make a speaker's voice sound like?
  7. Windows 11's hardware requirements call for which Trusted Platform Module (TPM) version?
  8. What is the passing score for the CompTIA A+ Core 1 (220-1201) exam?
  9. Which domain carries the largest share of the CompTIA A+ Core 1 (220-1201) exam?
  10. In CompTIA's troubleshooting methodology, which step comes first?
  11. Which port number does a DHCP server listen on?
  12. File sharing between Windows computers uses SMB. Which port does SMB use?
  13. Which port does Remote Desktop Protocol (RDP) use by default?
  14. Which port does Network Time Protocol (NTP) use to keep clocks in sync?
  15. Which protocol, defined in RFC 768, does not guarantee delivery of its datagrams?
  16. How many messages make up the TCP connection setup, known as the handshake?
  17. Which of these is a private IPv4 range reserved by RFC 1918?
  18. A PC cannot reach a DHCP server and gives itself an address. What does that address start with?
  19. How long is an IPv6 address?
  20. Which DNS record type maps a name to an IPv6 address?
  21. Which DNS record tells other servers where to deliver email for your domain?
  22. Which DNS record makes one name an alias for another name?
  23. Which DNS record type holds a domain's SPF policy for fighting spoofed email?
  24. What does DMARC let a domain owner publish for receiving mail servers?
  25. What is the first message a DHCP client sends when it needs an address?
  26. Which DHCP feature makes sure one specific device always gets the same IP address?
  27. In NIST's cloud definition, which trait lets capacity scale out and back in as demand changes?
  28. Using a provider's email app in your web browser is an example of which cloud service model?
  29. Which cloud model gives you virtual processing, storage and networks to run your own operating systems?
  30. A hypervisor that runs directly on the hardware with no host OS is called which type?
  31. What do containers on one host share that separate virtual machines do not?
  32. On a personal BYOD phone, which approach manages only the work apps and their data?
  33. Which RAID level writes identical data to each member disk?
  34. Which RAID level stripes data for speed but provides no redundancy?
  35. Which RAID level can recover from the loss of any two drives in the array?
  36. NVMe solid-state drives talk to the computer over which interface?
  37. Micron lists DDR5 memory data rates starting at which speed?
  38. Micron's DDR4 vs DDR5 table lists which chip feature as new in DDR5?
  39. USB 3.2 identifies three transfer rates. Which set is correct?
  40. What top speed does USB-IF list for USB4 over certified cables?
  41. What minimum bandwidth does Intel list for Thunderbolt 4?
  42. Which part of a laser printer bonds the toner to the paper with heat and pressure?
  43. What does the S.M.A.R.T. in drive health reports stand for?
  44. A drive health check warns the disk is about to fail. What should you do first?
  45. A laptop battery is swollen. What does Dell say to do with it?
  46. What is an eSIM?
  47. What false match rate does Apple state for Face ID with a single enrolled appearance?
  48. According to Android Help, which tethering method can Mac computers not use?
  49. Wi-Fi 7 adds 320 MHz wide channels in which frequency band?
  50. Which early IEEE 802.11 amendment defined a higher speed physical layer in the 5 GHz band?
  51. Which command scans protected Windows system files and repairs the damaged ones?
  52. Which command checks a disk volume's file system for logical and physical errors?
  53. Which command clears the Windows DNS client resolver cache?
  54. Which Windows command shows each router hop on the path to a destination?
  55. Which command reports latency and packet loss at each hop between you and a destination?
  56. Which netstat option adds the process ID (PID) for each active connection?
  57. Which command is used to diagnose DNS problems by querying name servers?
  58. Which command refreshes Group Policy settings on a Windows client right away?
  59. Which command shows which Group Policy settings actually applied to a user and computer?
  60. Which robocopy switch mirrors a directory tree, copying files and purging extras at the destination?
  61. Which MMC snap-in file opens Event Viewer to read system and application logs?
  62. Which MMC snap-in manages local user accounts and groups on a Windows PC?
  63. On what date did Microsoft end support for Windows 10?
  64. Which security chip version does Windows 11 require?
  65. What does User Account Control (UAC) do when a change needs administrator permission?
  66. Which Windows feature encrypts an entire drive volume to protect data on lost or stolen devices?
  67. Which feature encrypts removable drives such as USB flash drives in Windows?
  68. Which Windows feature encrypts individual files and folders on NTFS volumes?
  69. Windows Hello lets you sign in with biometrics or what other option instead of a password?
  70. Which Windows edition cannot act as a Remote Desktop host for incoming connections?
  71. For BitLocker to work, the operating system drive must be formatted with which file system?
  72. Which partitioning scheme was introduced as part of the UEFI initiative?
  73. What does System Restore do?
  74. What does Safe Mode do when Windows starts?
  75. Why does Windows show a blue screen stop error?
  76. What does PowerShell's execution policy control?
  77. Which built-in macOS feature automatically backs up your Mac to an external drive?
  78. Which macOS feature encrypts the startup disk so data needs the login password?
  79. How do you force quit an unresponsive Mac app from the menu bar?
  80. Which keyboard shortcut opens Spotlight search on a Mac?
  81. In macOS, what are the extra desktops that Mission Control lets you create called?
  82. Which Disk Utility feature checks and repairs a Mac volume?
  83. Which file system is the default for Mac computers using macOS 10.13 or later?
  84. Which Linux command changes a file's permission bits?
  85. Which Linux command reports free and used space on mounted file systems?
  86. Which file holds the shadowed password information for Linux accounts?
  87. Which Linux file describes the filesystems the system can mount?
  88. Which Linux command lets a permitted user run a command as the superuser or another user?
  89. Which Linux command checks and optionally repairs a filesystem?
  90. Which is a common warning sign of a phishing message?
  91. A hardware security key is an example of which authentication factor?
  92. Which principle says users should get only the minimum access needed to do their job?
  93. Which type of malware is designed to hide itself and keep stealthy access to a host?
  94. Which malware appears to be useful software but hides a malicious function?
  95. What makes a denial-of-service attack 'distributed'?
  96. Which Wi-Fi security standard adds stronger protection against password guessing on home networks?
  97. In incident response, what does chain of custody document?
  98. What should you do before opening a PC to repair it?
  99. In change management, which item describes how to undo a change if it fails?
  100. What is the right way to dispose of a worn-out lithium-ion laptop battery?