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CompTIA A+ Core 1 — Networking and Troubleshooting flashcards

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Ports and protocols, TCP versus UDP, Wi-Fi standards, SOHO devices, IP addressing, DHCP and DNS, cables and tools, and symptom-to-cause cards for Core 1, plus the CompTIA troubleshooting method in order, which the 220-1201 objectives describe but do not test.

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Learn deck · part of CompTIA A+ · written against: Core 1 (220-1201) and Core 2 (220-1202) exam objectives. Updated 2026-10-10.

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  1. During an FTP session, which port carries the commands and which carries the file data?
    TCP 21 is the control (command) channel and TCP 20 carries data in active mode.
    Networking › Ports and Protocols
  2. An administrator needs an encrypted command-line session to a Linux server. Which protocol and port, and what cleartext protocol does it replace?
    SSH on TCP 22. It replaces Telnet on TCP 23, which sends everything, including passwords, in cleartext.
    Networking › Ports and Protocols
  3. A mail server must accept messages relayed from other mail servers. Which inbound port must be open?
    TCP 25, used by SMTP for server-to-server mail transfer.
    Networking › Ports and Protocols
  4. An email client downloads messages to one PC and, by default, removes them from the server. Which protocol and port is it using?
    POP3 on TCP 110.
    Networking › Ports and Protocols
  5. A user reads the same mailbox on a phone and a laptop and wants folders and read status to stay in sync. Which retrieval protocol and port fit?
    IMAP on TCP 143. IMAP keeps mail on the server and synchronizes state across devices, unlike POP3.
    Networking › Ports and Protocols
  6. What are the six steps of the CompTIA troubleshooting methodology, in order?
    1. Identify the problem.
    2. Establish a theory of probable cause.
    3. Test the theory.
    4. Establish a plan of action and implement the solution.
    5. Verify full system functionality and, if needed, add preventive measures.
    6. Document findings, lessons learned, actions and outcomes.

    Not in the CompTIA A+ 2026 outline; background only.
    Hardware and Network Troubleshooting › Troubleshooting Methodology
  7. While identifying a problem, what should a technician do before making any changes to the user's system?
    Back up the data, after gathering information from the user and asking about recent changes to the system or its environment.

    Not in the CompTIA A+ 2026 outline; background only.
    Hardware and Network Troubleshooting › Troubleshooting Methodology
  8. A technician replaces a failed power supply and the PC boots. Which step comes next before closing the ticket?
    Verify full system functionality and, where appropriate, put preventive measures in place. Then document the findings, actions and outcomes.

    Not in the CompTIA A+ 2026 outline; background only.
    Hardware and Network Troubleshooting › Troubleshooting Methodology
  9. A PC powers on, fans spin, but there is no POST and a sequence of beeps sounds. What do the beeps tell you?
    They are POST beep codes reporting a hardware fault found before video starts, commonly RAM or graphics. The meaning depends on the firmware vendor, so look up the motherboard manual.
    Hardware and Network Troubleshooting › Motherboards RAM CPU and Power
  10. A PC shuts down at random after running for a while, especially under heavy load. What is the most likely cause?
    Overheating: check for dust-clogged heat sinks, failed fans, blocked airflow or failing thermal paste. A failing power supply is the next suspect.
    Hardware and Network Troubleshooting › Motherboards RAM CPU and Power

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About these cards

Review status: Second-reader reviewed, with corrections applied.

Checked against:

  • Checked against the IANA Service Name and Transport Protocol Port Number Registry (public) and RFC 1918 and RFC 3927 for private and link-local addressing (reference only; no text copied).
  • Checked against IEEE 802.11 and 802.3 standard summaries and the TIA-568 cabling standard summaries (reference only; no text copied).
  • CompTIA A+ exam objectives 220-1201/220-1202 (topic outline only; no text copied)
  • Checked against NIST Technical Note 1291 (UL 910 plenum cable test), UL Code Authorities guidance on NFPA 262 plenum cable, Southwire and Extron plenum-cable documentation, and Mike Holt's EC&M Code Q&A on wiring methods in air-handling spaces (reference only; no text copied).

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