Full Form of ALG

What is ALG?

An Application Layer Gateway (ALG) is a network security component that operates at the application layer (Layer 7) of the OSI model. It acts as a proxy or intermediary for specific application protocols such as FTP, SIP, H.323, and DNS. Unlike a traditional packet filter firewall, an ALG inspects the payload of packets, understands the protocol semantics, and can modify headers or dynamically open ports to allow legitimate traffic while blocking malicious requests. In India, ALGs are widely deployed in enterprise networks, data centers, and telecom infrastructure to secure services like VoIP, video conferencing, and file transfers. For students preparing for GATE Computer Science, understanding ALG is crucial in the computer networks syllabus, where it is compared with stateful inspection and circuit-level gateways. The concept also features in networking certifications like CCNA and CEH. An ALG enhances security by preventing protocol-based attacks such as FTP bounces and SIP registration hijacking. It is commonly used alongside firewalls and intrusion prevention systems to enforce granular policies. The main limitation is performance overhead due to deep packet inspection, but modern appliances mitigate this with hardware acceleration. Overall, ALG remains a foundational building block in layered network security, especially in environments requiring application-aware filtering.

ALG का फुल फॉर्म

Example

The IT team enabled the ALG on the firewall to ensure secure file transfers over FTP without exposing the internal network directly.

ALG — frequently asked questions

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