LFCS Certification Network Service Configuration 2

Question 1

Which command displays the current listening TCP and UDP ports along with the process using each port?

Accepted Answer

netstat -tulpn

Answer

ifconfig -a

Answer

ip route show

Answer

nmap localhost

Question 2

Which file must you edit to make a custom DNS name resolve locally before querying external DNS servers?

Accepted Answer

/etc/hosts

Answer

/etc/resolv.conf

Answer

/etc/nsswitch.conf

Answer

/etc/hostname

Question 3

What is the purpose of the /etc/resolv.conf file?

Accepted Answer

Lists DNS nameserver addresses and search domains

Answer

Defines static IP routes

Answer

Maps MAC addresses to IPs

Answer

Configures firewall rules

Question 4

Which systemd unit type is used to expose a service on a network socket, enabling socket activation?

Accepted Answer

.socket

Answer

.service

Answer

.target

Answer

.mount

Question 5

You want to test whether TCP port 443 is open on a remote host without installing extra tools. Which command works on most Linux systems?

Accepted Answer

bash -c 'echo > /dev/tcp/host/443'

Answer

ping -p 443 host

Answer

curl -k https://host

Answer

traceroute --port=443 host

Question 6

Which directive in an SSH server configuration (/etc/ssh/sshd_config) disables password-based logins?

Accepted Answer

PasswordAuthentication no

Answer

AllowPasswords no

Answer

UsePAM no

Answer

PubkeyOnly yes

Question 7

Which command reloads the systemd daemon after editing a unit file, without restarting services?

Accepted Answer

systemctl daemon-reload

Answer

systemctl restart

Answer

systemctl reload

Answer

systemctl refresh

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