How does firewall affect network security?

A firewall acts as a barrier between a trusted internal network and untrusted external networks, such as the internet, by monitoring and controlling incoming and outgoing traffic based on predetermined security rules. It helps prevent unauthorized access, cyberattacks, and data breaches by filtering out potentially harmful traffic. Additionally, firewalls can log activities and alerts, allowing for better threat detection and response. Overall, they are a critical component in maintaining the integrity and security of network environments.