LFCS Certification Firewall and Packet Filtering 5

Question 1

Which iptables option is used to insert a rule at a specific position in a chain rather than appending it?

Accepted Answer

-I

Answer

The '-I' (--insert) option inserts a rule at a specified position, while '-A' always appends to the end of the chain.

Question 2

In firewalld, which command lists all active zones along with their associated interfaces?

Accepted Answer

firewall-cmd --get-active-zones

Answer

The --get-active-zones option shows only zones that have interfaces or sources assigned, along with those assignments.

Question 3

Which nftables verdict terminates packet processing and accepts the packet?

Accepted Answer

accept

Answer

In nftables, 'accept' is the terminal verdict that allows the packet to continue through the network stack.

Question 4

What kernel parameter must be set to '1' to enable IPv4 packet forwarding for firewall/routing use?

Accepted Answer

net.ipv4.ip_forward

Answer

Setting net.ipv4.ip_forward=1 via sysctl enables the kernel to forward packets between network interfaces.

Question 5

Which iptables module allows rate limiting connections to prevent brute-force attacks?

Accepted Answer

-m limit

Answer

The '-m limit' module throttles rule matching to a maximum rate, commonly used to limit log entries or new connection attempts.

LFCS Certification Practice Test