What is an application gateway in information security?

Application Gateway is a type of firewall that supports application-level control over network traffic. Application gateways can be used to deny access to the resources of private networks to distrusted clients over the web.

An application gateway is an application program that runs on a firewall system between two networks. When a client program creates a link to a destination service, it connects to an application gateway, or proxy. The client then compromise with the proxy server to interact with the destination service. In effect, the proxy creates the connection with the destination behind the firewall and acts on behalf of the client, hiding and securing individual computers on the network behind the firewall.

This creates two connections such as one between the client and the proxy server and one between the proxy server and the destination. Because connected, the proxy creates all packet-forwarding decisions. Because all communication is conducted through the proxy server, computers behind the firewall are secured.

An application gateway works by determining incoming packets or data blocks at the application or program level. It uses proxies to create a private connection for remote users. So, consider an external user tries to gain access to an internal company server. In that case, it automatically runs a proxy or an example of the application that replicates the server’s functions is accessing. That way, the actual application is not influenced by anything that the client does.

Application gateways determines incoming packets at the application level and use proxies to make secure sessions with remote users. For instance, when an external user with a Web browser attempt to access the company’s internal internet server, the application gateway runs a proxy application that simulates the internal internet server.

A session is created between the remote user and the proxy application, while a separate, independent session is created between the proxy application and the internal internet server. The remote user creates a request to the proxy, the proxy acts as a go-between and acquire the data from the internal internet server, and then the proxy returns the result to the remote user.

The benefit of using application gateways over packet-filtering routers is that in packet filtering, a direct network connection still exists among the remote user and the internal network resource, while an application gateway avoids the remote user from directly accessing the internal network resource.

This layer of more security appears at some cost, such that application gateways are generally slower and needed a separate proxy application for each internal network service it is required to make available through the firewall.

Application gateways are also hugely preferred over packet filtering routers because the latter uses direct network connections. It also supports that application gateways provide computers a comprehensive list of some incoming traffic. That appears in handy when recognizing malicious attempts of hacking into a network.