What is the main purpose of a firewall?

The main purpose of a firewall is to protect against unauthorized access by filtering network traffic. Firewalls act as a barrier between trusted internal networks and untrustworthy external networks, such as the internet. They monitor incoming and outgoing traffic and determine whether to allow or block specific traffic based on a defined set of security rules.

By effectively controlling this access, firewalls help prevent malicious activities, such as hacking attempts, unauthorized data breaches, and other security threats. They can also log traffic and provide insights that help improve overall network security. This makes the role of firewalls crucial in maintaining the integrity and confidentiality of sensitive data within a network.

The other options do not accurately capture the purpose of a firewall. Sending hoax messages is unrelated to network security and could actually endanger it. Encoding data is a method of securing information but does not relate directly to the core function of a firewall. Evaluating ethical standards is not a technical function of firewalls but rather pertains to organizational policies and compliance.