What is the main function of a firewall in a network?

The main function of a firewall in a network is to monitor and control network traffic. Firewalls act as security devices or software that establish a barrier between trusted internal networks and untrusted external networks, such as the internet. Their primary role is to filter incoming and outgoing traffic based on predetermined security rules. This means they evaluate data packets and determine whether they should be allowed through the network according to the security policies set by the network administrator.

By analyzing various characteristics of the traffic, including protocols, port numbers, and source/destination addresses, firewalls help prevent unauthorized access, protect sensitive information, and manage bandwidth by allowing only legitimate traffic to pass. They can also log traffic data, which can be invaluable for diagnosing potential security issues or breaches in the network.

The other options do not accurately represent the sole role of a firewall. While creating computer programs relates to software development, storing user credentials pertains to authentication systems, and accelerating internet speed does not fall within the typical functionalities of a firewall. Firewalls focus primarily on traffic monitoring and control, serving as a crucial element in cybersecurity strategies.