Editing Proxy server (section)

===Comparison to network address translators===
The proxy concept refers to a layer-7 application in the [[OSI model|OSI reference model]]. [[Network address translation]] (NAT) is similar to a proxy but operates in layer 3.

In the client configuration of layer-3 NAT, configuring the gateway is sufficient. However, for the client configuration of a layer-7 proxy, the destination of the packets that the client generates must always be the proxy server (layer 7), then the proxy server reads each packet and finds out the true destination.

Because NAT operates at layer 3, it is less resource-intensive than the layer-7 proxy, but also less flexible. As we compare these two technologies, we might encounter a terminology known as 'transparent firewall'. '''Transparent firewall''' means that the proxy uses the layer-7 proxy advantages without the knowledge of the client. The client presumes that the gateway is a NAT in layer 3, and it does not have any idea about the inside of the packet, but through this method, the layer-3 packets are sent to the layer-7 proxy for investigation.{{Citation needed|date=July 2023}}