LFCS Certification Network Service Configuration 5

Question 1

Which command tests DNS resolution for the hostname 'example.com' using a specific nameserver at 8.8.8.8?

Accepted Answer

dig @8.8.8.8 example.com

Answer

dig's @ syntax directs the query to a specific nameserver, overriding /etc/resolv.conf.

Question 2

What does the 'Listen' directive in /etc/apache2/ports.conf or httpd.conf control?

Accepted Answer

Which IP addresses and ports Apache binds to

Answer

The Listen directive tells Apache which IP:port combinations to accept incoming connections on.

Question 3

Which command starts and enables a service to start at boot using systemd in a single step?

Accepted Answer

systemctl enable --now sshd

Answer

systemctl enable --now combines enabling at boot and immediately starting the service in one command.

Question 4

A web server needs to serve content over HTTPS. Which port must be open in the firewall by default?

Accepted Answer

443

Answer

HTTPS uses TCP port 443 by default as defined in IANA port assignments.

Question 5

Which iptables command allows established and related traffic to pass through, supporting stateful inspection?

Accepted Answer

iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT

Answer

The conntrack module with ESTABLISHED,RELATED states permits return traffic for existing connections.

LFCS Certification Practice Test