What is a firewall's main function in a computer network?

A firewall's primary role in a computer network is to monitor and control traffic flowing in and out of that network. This function is crucial for maintaining the security and integrity of the network environment. Firewalls act as a barrier between a trusted internal network and untrusted external networks, such as the internet. By doing so, they examine incoming and outgoing packets of data based on a set of predetermined rules to determine whether to allow or block specific traffic.

For example, firewalls can prevent unauthorized users from accessing sensitive data or inhibit malicious attacks such as malware and hacking attempts. They can also enforce organizational security policies by controlling what types of data can be transmitted and received, thus ensuring that only safe and necessary traffic is allowed.

The other options do not accurately describe the main function of a firewall. Providing high-speed internet access pertains to the role of internet service providers and is not directly related to firewalls. Storing data securely is a function more associated with storage solutions and databases rather than firewalls. Lastly, managing user accounts is typically a function of identity management systems or directory services, which is outside the scope of what a firewall does.