An application-level gateway (ALG) is a device or software program that provides a secure and efficient way to connect applications to a network. ALGs operate at the application layer of the OSI model, which is the highest layer of the model and is responsible for providing application-specific functionality. This allows ALGs to understand the specific needs of each application and to provide the necessary services to support those needs.
ALGs are typically used to provide security, load balancing, and protocol translation services. Security features provided by ALGs include firewall protection, intrusion detection, and encryption. Load balancing features provided by ALGs include the ability to distribute traffic across multiple servers and to provide failover support. Protocol translation features provided by ALGs include the ability to convert between different network protocols, such as TCP and UDP.
