How does a firewall enhance network security?

A firewall enhances network security primarily by monitoring incoming and outgoing network traffic. This function allows the firewall to inspect data packets and enforce security policies, determining which traffic is permitted or denied based on predefined rules. By continuously monitoring this traffic, the firewall can help to prevent unauthorized access to the network and protect sensitive data from potential threats such as hackers and malware.

In contrast, while increasing the speed of data transmission can be a beneficial feature of some network configurations, it is not a primary function of a firewall. Additionally, backup solutions for users are unrelated to the firewall's capabilities, as these functions typically involve different types of software and hardware solutions aimed at data recovery rather than security. Finally, although antivirus software and firewalls can complement each other in a comprehensive security strategy, firewalls do not replace the need for antivirus solutions, as they address different aspects of network security.