Firewall and Packet Filtering Flashcards
7 cards from real LFCS Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Firewall and Packet Filtering flashcards as text
Which iptables table is used for Network Address Translation (NAT)?
Answer: nat
The 'nat' table is specifically designed for NAT operations including SNAT, DNAT, and MASQUERADE.
What iptables command lists all rules in the filter table with line numbers?
Answer: iptables -L -v --line-numbers
The '-L -v --line-numbers' flags list all rules verbosely with line numbers for easy reference and deletion.
Which firewalld zone is most appropriate for a network interface connected to the public internet?
Answer: public
The 'public' zone assumes the network is untrusted and only allows selected incoming connections.
How do you make firewalld rule changes permanent so they survive a reboot?
Answer: firewall-cmd --permanent followed by --reload
The --permanent flag writes rules to disk, and --reload applies them to the running configuration.
In nftables, what command adds a new table named 'mytable' with the inet family?
Answer: nft add table inet mytable
The 'nft add table' command creates a new nftables table with the specified address family.
Which iptables target silently discards a packet without sending any response to the sender?
Answer: DROP
DROP silently discards the packet, while REJECT sends an ICMP error message back to the sender.
What does the iptables MASQUERADE target do?
Answer: Replaces the source IP with the outgoing interface's IP dynamically
MASQUERADE automatically substitutes the source IP with the current IP of the outgoing interface, ideal for dynamic IPs.
How this page was made: written with AI tools and published by Nathan Beja, founder of Practice Test Geeks, who is responsible for its content. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy
Sources & references
Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy
- docs.linuxfoundation.org — Renewal, score release, exam format, passing score · verified Oct 2026
- training.linuxfoundation.org — Test delivery, eligibility, fees, registration deadline, time limit, score validity · verified Oct 2026