The significance of firewall rules in network security lies in their ability to control the flow of traffic and protect internal networks from unauthorized access. Firewalls establish predefined rules to allow or block specific incoming and outgoing data packets based on criteria such as IP addresses, protocols, and port numbers. By implementing effective firewall rules, organizations can mitigate the risk of cyberattacks, data breaches, and unauthorized access attempts. Firewalls play a critical role in safeguarding sensitive information and maintaining the overall security posture of networked environments.