LFCS Timed Practice Test 2 — 10 Questions

Question 1

A system administrator needs to mount an ext4 filesystem with the options 'noatime' and 'errors=remount-ro'. Which mount command is correct?

Accepted Answer

mount -o noatime,errors=remount-ro /dev/sda1 /mnt. The `mount -o noatime,errors=remount-ro /dev/sda1 /mnt` command uses a single `-o` flag with a comma-separated list of mount options, which is the proper syntax for specifying multiple options. The `noatime` option disables updating the access time on reads, and `errors=remount-ro` tells the kernel to remount the filesystem as read-only if an I/O error is encountered, both of which are valid ext4 mount options.

Answer

mount -o noatime,errors=remount /dev/sda1 /mnt

Answer

mount -o noatime -o errors=remount-ro /dev/sda1 /mnt

Answer

mount -o atime=no,errors=remount-ro /dev/sda1 /mnt

Question 2

A system administrator needs to ensure that a Linux server can communicate with other hosts on the same subnet. Which command should be used to verify the IP address and netmask configuration?

Accepted Answer

ip addr show. The `ip addr show` command is the modern, recommended tool in Linux for viewing IP addresses and netmasks (prefix lengths) assigned to network interfaces. It directly displays the configuration needed to verify subnet communication, unlike legacy tools that may not show the netmask clearly or mix routing information.

Answer

netstat -rn

Answer

route -n

Answer

ifconfig

Question 3

A user reports that they cannot reach a remote server by hostname but can reach it by IP address. Which configuration file is most likely misconfigured?

Accepted Answer

/etc/resolv.conf. The /etc/resolv.conf file configures the system's DNS resolver, specifying the nameservers to query for hostname-to-IP resolution. If a user can reach a server by IP but not by hostname, it indicates that DNS resolution is failing, which is most commonly due to a missing or incorrect nameserver entry in /etc/resolv.conf.

Answer

/etc/sysconfig/network

Answer

/etc/hosts

Answer

/etc/nsswitch.conf

Question 4

A system administrator needs to schedule a one-time task that will run at 2:30 AM on July 15. Which command should be used to create this job?

Accepted Answer

at 2:30 AM July 15. The at command is specifically designed for scheduling one-time tasks at a precise date and time. Using at 2:30 AM July 15 allows the administrator to queue a command that will execute once at that moment, fulfilling the requirement.

Answer

crontab -e

Answer

systemd-run --on-calendar="*-07-15 02:30:00"

Answer

batch

Question 5

An administrator needs to compress a directory named 'project' into a tarball with maximum compression using gzip. Which command is appropriate?

Accepted Answer

tar -czvf archive.tar.gz project. The `-z` flag tells tar to compress the archive using gzip. The `-c` flag creates a new archive, `-v` provides verbose output, and `-f` specifies the archive filename. The `.tar.gz` extension is the conventional extension for a gzip-compressed tarball. Although other tools like bzip2 or xz can achieve higher compression ratios, the question explicitly asks for using gzip.

Answer

tar -cjvf archive.tar.bz2 project

Answer

tar -cJvf archive.tar.xz project

Answer

tar -cvf archive.tar project

Question 6

An administrator is configuring a bridge using iproute2. Which command correctly attaches eth0 to bridge br0?

Accepted Answer

ip link set eth0 master br0. The `ip link set eth0 master br0` command attaches the physical interface `eth0` as a slave port of the bridge `br0` using the iproute2 suite. The `master` keyword specifies the bridge device that should become the master of the specified interface, which is the standard way to add an interface to a bridge with iproute2.

Answer

ip link set br0 master eth0

Answer

nmcli device modify eth0 master br0

Answer

brctl addif br0 eth0

Question 7

A security policy requires that all users in the 'admin' group must have a umask of 027 set automatically upon login. An administrator adds 'umask 027' to /etc/profile. However, users report that the umask is still 022. What is a likely cause?

Accepted Answer

The umask in /etc/profile is overridden by user-specific .bash_profile or .bashrc files.. User-specific shell configuration files (like ~/.bash_profile, ~/.bash_login, or ~/.profile for login shells, and ~/.bashrc for interactive non-login shells) are sourced after /etc/profile. These files can override the system-wide umask setting with a user-defined value, such as the default 022. Since the administrator only modified /etc/profile, any existing user-specific umask command in their personal dotfiles will take precedence.

Answer

The umask command in /etc/profile has a syntax error that is silently ignored.

Answer

The admin placed the umask command after the call to /etc/bash.bashrc which resets it.

Answer

The admin forgot to run 'source /etc/profile' on each user's session.

Question 8

A systems administrator needs to add a new user 'jdoe' with a home directory in /export/home, a UID of 1500, and an expiry date of 2025-12-31. Which command should they use?

Accepted Answer

useradd -u 1500 -d /export/home/jdoe -e 2025-12-31 jdoe. The `useradd` command with `-u 1500` sets the UID, `-d /export/home/jdoe` explicitly specifies the home directory path (without creating it unless `-m` is also used), and `-e 2025-12-31` sets the account expiry date in YYYY-MM-DD format. This matches all requirements: UID 1500, home directory at /export/home/jdoe, and expiry on 2025-12-31.

Answer

useradd -u 1500 -d /export/home/jdoe -c 2025-12-31 jdoe

Answer

useradd -u 1500 -m -e 2025-12-31 jdoe

Answer

useradd -u 1500 -b /export/home -e 2025-12-31 jdoe

Question 9

You administer a Linux server that acts as a network gateway. It has two network interfaces: eth0 (external, with IP 203.0.113.10/24, gateway 203.0.113.1) and eth1 (internal, with IP 192.168.1.1/24). The server is running firewalld and has IP forwarding enabled. Internal hosts (192.168.1.0/24) can access the internet through NAT, which is configured using firewalld's masquerade on the external zone. However, you need to allow a specific internal server (192.168.1.100) to be reachable from the internet on TCP port 443 (HTTPS). You add a port forwarding rule using firewall-cmd: 'firewall-cmd --zone=external --add-forward-port=port=443:proto=tcp:toport=443:toaddr=192.168.1.100'. After reloading the firewall, external users still cannot connect to 203.0.113.10:443. You verify that the internal server is running HTTPS and that its local firewall allows port 443. What is the most likely reason the port forwarding is not working?

Accepted Answer

The rule needs to include masquerade for the destination address; use a rich rule with 'masquerade'.. A simple port forward rule in firewalld does not automatically rewrite the source IP address for return traffic. Without masquerade on the forwarded traffic, the internal server sees the original external source IP and sends its response directly to that IP, bypassing the gateway. Adding a rich rule with 'masquerade' for the destination address ensures that the gateway performs SNAT on the forwarded packets, so the internal server sees the gateway as the source and returns traffic through it.

Answer

The port forwarding rule should be added to the internal zone instead of the external zone.

Answer

The internal server has a different default gateway.

Answer

IP forwarding is not enabled on the system.

Question 10

An administrator wants to ensure that a service starts automatically after a system crash. Which systemd command should be used?

Accepted Answer

systemctl enable service. The `systemctl enable service` command creates the necessary symlinks in the systemd unit configuration directories (e.g., `/etc/systemd/system/multi-user.target.wants/`) so that the service is automatically started at boot. This includes recovery after a system crash, because the crash triggers a reboot, and the enabled service will be started as part of the normal boot process.

Answer

systemctl daemon-reload

Answer

systemctl mask service

Answer

systemctl start service