Practice Test Geeks(LCA) Certified Linux Administrator Practice Test
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Network Configuration & Troubleshooting Flashcards

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

Read the first 7 Network Configuration & Troubleshooting flashcards as text

  1. Which command displays the current routing table on a Linux system using the iproute2 suite?

    Answer: ip route show

    The 'ip route show' command from the iproute2 suite displays the kernel routing table.

  2. A server cannot reach hosts outside its subnet. The default gateway is set to 192.168.1.1, but pinging it fails. What is the FIRST step to diagnose this?

    Answer: Check if the gateway IP is reachable via ARP using 'arping'

    Using 'arping' confirms whether the gateway's MAC address is reachable at Layer 2 before investigating higher-layer issues.

  3. Which file in a Red Hat-based system stores the DNS resolver configuration?

    Answer: /etc/resolv.conf

    The /etc/resolv.conf file specifies nameserver addresses and search domains used by the resolver library.

  4. What does the 'ss -tulpn' command display?

    Answer: Listening TCP and UDP sockets with associated process names

    'ss -tulpn' lists all listening (-l) TCP (-t) and UDP (-u) sockets with process names (-p) and numeric ports (-n).

  5. You want to add a static route so that traffic to 10.20.0.0/24 goes through gateway 192.168.1.254 permanently on a systemd-networkd system. Where do you configure this?

    Answer: A .network file in /etc/systemd/network/ with a [Route] section

    systemd-networkd reads .network files in /etc/systemd/network/ where [Route] sections define static routes.

  6. Which tool performs a path MTU discovery test to a remote host to detect where packets are being fragmented?

    Answer: tracepath

    'tracepath' probes each hop along the route and reports the PMTU by sending incrementally larger UDP packets.

  7. A host has two NICs: eth0 (192.168.1.10/24) and eth1 (10.0.0.5/24). Traffic to 10.0.0.0/24 is unexpectedly using eth0. What is the most likely cause?

    Answer: A more specific route for 10.0.0.0/24 is missing, so the default route via eth0 is used

    Without a specific route for 10.0.0.0/24 via eth1, the kernel falls back to the default route, which exits through eth0.