On a Linux system, which command allows you to modify settings used by the built-in packet filtering firewall?

a.

ipf

b.

iptables

c.

netwall

d.

modfire

iptables

Explanation:

On a Linux system, iptables command allows us to modify settings of the built-in packet filtering firewall.

Iptables is used to set up, maintain, inspect and update the tables of IP packet filtering rules on Linux.

For example,

To view the current rule settings we can use the command:

# iptables - L - n - v

To add new firewall rules:

# iptables - I INPUT - s - j DROP