An application layer gateway (ALG) is a network device that operates at the application layer of the Open Systems Interconnection (OSI) model. It mediates communication between two networks, typically a private network and a public network, such as the internet. ALGs are used to provide security, access control, and other services.
ALGs are important because they can help to protect networks from attack, ensure that only authorized users can access certain resources, and improve the performance of network applications. For example, an ALG can be used to:
