COMPUTER FUNDAMENTALS

Detailed explanation-1: -A firewall establishes a border between an external network and the network it guards. It is inserted inline across a network connection and inspects all packets entering and leaving the guarded network. As it inspects, it uses a set of pre-configured rules to distinguish between benign and malicious packets.

Detailed explanation-2: -An internal firewall is a security solution designed to protect a network from attacks that have already gotten past the perimeter. A firewall, in general, is a device or software designed to monitor traffic and prevent unauthorized access, and an internal firewall is an advanced application of that concept.