Application-level gateway (ALG) firewalls play a crucial role in network security by providing advanced inspection and filtering capabilities at the application layer of the OSI model. Unlike traditional firewalls that operate at the network or transport layer, ALG firewalls can examine and control traffic based on specific application protocols. This enables them to detect and block malicious activities such as unauthorized access, data exfiltration, and application-layer attacks. ALG firewalls also offer granular control over application traffic, allowing administrators to enforce security policies tailored to individual applications. By monitoring and filtering traffic at a deeper level, ALG firewalls enhance overall network security posture.