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System Administration Flashcards

7 cards from real Linux practice questions. Tap to flip, then mark Knew It or Still Learning โ€” missed cards come back until you master them.

Read the first 7 System Administration flashcards as text
  1. What is the purpose of the `/etc/hosts.allow` and `/etc/hosts.deny` files?

    Answer: Define TCP Wrappers access control rules

    TCP Wrappers reads `/etc/hosts.allow` and `/etc/hosts.deny` to permit or block connections to wrapped services.

  2. Which command would display all open network ports and the processes listening on them?

    Answer: netstat -tulpn

    `netstat -tulpn` shows TCP/UDP listening ports with the process name/PID (requires root for all processes).

  3. You want to find all files modified in the last 24 hours under `/var/log`. Which command is correct?

    Answer: find /var/log -mtime -1

    `-mtime -1` matches files modified less than 1 day (24 hours) ago; the minus sign means 'less than'.

  4. What is the primary function of `logrotate`?

    Answer: Manages automatic rotation, compression, and deletion of log files

    `logrotate` automatically rotates, compresses, removes, and mails log files based on rules in `/etc/logrotate.conf`.

  5. Which `iptables` chain filters packets destined for the local system?

    Answer: INPUT

    The INPUT chain processes packets destined for the local machine's own network stack.

  6. What does the `lsblk` command display?

    Answer: Block device tree showing disks and partitions

    `lsblk` lists block devices in a tree format showing disks, partitions, and their mount points.

  7. A service fails to start and you see 'Unit not found'. What is the most likely cause?

    Answer: The unit file does not exist or is not in the search path

    'Unit not found' means systemd cannot locate the service's unit file in any of its configured directories.