Use of firewall plays an integral role in EchoMail's overall network security. Before going into details describing all of the components that comprise network security infrastructure, we would first have to analyze the importance and relativity of firewall security requirements and their implementation.

The firewall is a security system for preventing unauthorized communications between one computer network and another computer network and more specifically for preventing unauthorized access to a private computer network from a public computer network such as the Internet.

Mechanisms of firewalls use the Open Systems Interconnections (OSI) and Transmission Control Protocol/Internet Protocol (TCP/IP) Reference Models.