LFCS Practice Test 18 — 15 Questions

Question 1

Match each Linux boot component to its description.

Question 2

Match each systemd unit type to its purpose.

Question 3

Match each Linux package management command to its distribution.

Question 4

Match each Linux command to its function.

Question 5

Match each Linux permission type to its symbolic representation.

Question 6

Match each Linux networking command to its primary function.

Question 7

Match each file system type to its typical use case.

Question 8

Match each Linux process signal to its numeric value.

Question 9

Based on the exhibit, which port is listening only on the loopback interface?

Accepted Answer

53. Option A is correct because port 53 (DNS) is configured to listen only on the loopback interface (127.0.0.1) as shown in the exhibit's output of `ss -tlnp`. The listening address `127.0.0.1:53` indicates the service is bound exclusively to the loopback interface, meaning it is not accessible from external network interfaces.

Answer

22

Answer

443

Answer

80

Question 10

A system administrator needs to permanently configure a network interface named ens33 with a static IPv4 address of 192.168.1.100/24 and a default gateway of 192.168.1.1 on a system using NetworkManager. Which command should the administrator use to achieve this?

Accepted Answer

nmcli connection modify 'ens33' ipv4.addresses 192.168.1.100/24 ipv4.gateway 192.168.1.1 ipv4.method manual. Option A is correct because it uses the `nmcli` command to modify the NetworkManager connection profile for interface ens33, setting a static IPv4 address with CIDR notation and a default gateway, and explicitly setting the method to 'manual' to ensure the configuration persists across reboots. NetworkManager is the default network service on modern Linux distributions, and `nmcli` is the proper tool for permanent configuration changes.

Answer

ip addr add 192.168.1.100/24 dev ens33

Answer

ifconfig ens33 192.168.1.100 netmask 255.255.255.0 up

Answer

route add default gw 192.168.1.1 ens33

Question 11

Which TWO are valid methods to configure a network interface on a Linux system?

Accepted Answer

Editing /etc/network/interfaces. Option C is correct because /etc/network/interfaces is the traditional configuration file used by the ifup/ifdown system on Debian-based distributions to define network interfaces, including IP addresses, netmasks, and gateways. This file is parsed by the ifup command to bring interfaces up with the specified settings, making it a valid method for persistent network configuration.

Answer

Using sysctl to set net.ipv4.conf.eth0.forwarding

Answer

Using systemctl enable network.service

Answer

Editing /etc/sysconfig/network

Question 12

A server has two network interfaces: eth0 (10.0.0.10/24) and eth1 (192.168.1.10/24). The server needs to act as a router for a subnet 172.16.0.0/24, forwarding packets between it and the 10.0.0.0/24 network. Which sysctl parameter must be set to a value of 1 to enable IP forwarding?

Accepted Answer

net.ipv4.ip_forward. Option D is correct because `net.ipv4.ip_forward` is the primary sysctl parameter that controls IP forwarding at the kernel level on Linux systems. Setting it to 1 enables the kernel to forward packets between network interfaces, which is essential for the server to act as a router between the 172.16.0.0/24 and 10.0.0.0/24 subnets.

Answer

net.ipv4.conf.all.forwarding

Answer

net.core.forwarding

Answer

net.ipv4.tcp_forwarding

Question 13

A system administrator is troubleshooting network connectivity from a server that can reach internal resources but cannot access the internet. The server's /etc/sysconfig/network-scripts/ifcfg-eth0 file contains: BOOTPROTO=static, IPADDR=10.0.0.10, NETMASK=255.255.255.0, GATEWAY=10.0.0.1. The administrator runs 'ip route show' and sees: default via 10.0.0.1 dev eth0. However, 'ping 8.8.8.8' fails. Which is the most likely cause?

Accepted Answer

The gateway 10.0.0.1 is not configured to forward traffic to the internet (no NAT or upstream route).. The routing table shows a default gateway (10.0.0.1) is present, so the issue is not a missing route. Since the server can reach internal resources but not the internet, the most likely cause is that the gateway itself (10.0.0.1) is not configured to perform NAT or does not have an upstream route to forward traffic beyond the local subnet. Without this, packets destined for 8.8.8.8 are sent to the gateway but are then dropped because the gateway has no path to the internet.

Answer

The default gateway is missing from the routing table.

Answer

DNS resolution is not configured.

Answer

A firewall is blocking outbound ICMP traffic.

Question 14

Which THREE are common tools used for network troubleshooting on Linux?

Accepted Answer

traceroute. A. traceroute is correct because it uses ICMP (or UDP on some systems) to trace the path packets take to a destination, revealing each hop's IP address and round-trip time. This helps identify routing issues, packet loss, or latency bottlenecks in the network path.

Answer

fdisk

Answer

useradd

Question 15

A company has a server with two network interfaces: eth0 (192.168.1.10/24, gateway 192.168.1.1) and eth1 (10.0.0.10/24, gateway 10.0.0.1). The server needs to reach a remote network 172.16.0.0/16 via a VPN tunnel that terminates at 10.0.0.5 on eth1. Which command should be used to add a route for this traffic?

Accepted Answer

ip route add 172.16.0.0/16 via 10.0.0.5 dev eth1. Option A is correct because the VPN tunnel endpoint is at 10.0.0.5 on the eth1 network, so traffic to 172.16.0.0/16 must be forwarded via that next-hop IP address using the eth1 interface. The `ip route add` command with `via 10.0.0.5 dev eth1` explicitly sets the gateway and egress interface, ensuring packets are sent through the VPN tunnel.

Answer

ip route add 172.16.0.0/16 via 10.0.0.5 dev eth0

Answer

ip route add 172.16.0.0/16 via 192.168.1.1 dev eth0

Answer

ip route add 172.16.0.0/16 dev eth1