What are iptables used for in Linux systems?

Iptables is a user-space utility program that allows system administrators to configure the Linux kernel's packet filtering rules. It plays a crucial role in the Linux networking stack by enabling rules to control the flow of incoming and outgoing network packets. This capability is essential for implementing various security measures, such as allowing or blocking traffic based on IP addresses, protocols, ports, and other criteria. By defining these rules, iptables provides a means for maintaining the security of a Linux system, protecting it from unauthorized access or attacks.

The context of this tool highlights its significance in network administration and security, distinguishing it from options that revolve around different system functions like software package management, process management, or resource monitoring. Iptables specifically impacts how data packets are handled at the network level, reflecting its specialized role in the Linux environment.