HTTP (ii) proxy

Agent

Concept

A proxy server on the Web is the middleman who completes transactions on behalf of the client.

The HTTP proxy server is both a Web server and a Web client.

Classification

Public agents and private agents

The difference from the gateway

The agent is connected to two or more applications using the same protocol;

A gateway connects two or more endpoints that use different protocols.

The commercial proxy server also implements the Gateway function to support SSL security protocol, socks firewall, FTP access, etc.

Usage Scenarios

Filters, document controls, security firewalls, web caches, reverse proxies, content routers, transcoding, and more

Deployment of a proxy server

Export Agent: The agent is fixed at the exit point of the local network, control the traffic between the local network and the large Internet;

Access Agent: The agent is placed on the ISP access point, with the processing of aggregate requests from customers;

Reverse proxy: Usually deployed at the edge of the network, before the Web server, to replace processing requests;

Network switching agent: The agents with sufficient processing power are placed on the Internet peering point between the networks, and the Internet node congestion is mitigated by the cache, and the traffic is monitored.

Hierarchical structure of agents

Load balancing: The sub-agent decides to select a parent agent based on the workload level on the current parent agent to equalize the load;

Routing near geographic location: The child agent may choose to be the parent agent responsible for the physical region where the original server resides;

Protocol/Type Routing: the sub-agent may forward the message to a different parent agent and the original server based on the URI;

Subscription-based routing: If publishers pay extra for high-performance services, their URIs are forwarded to a large cache or compression engine to improve performance.

Set up Proxy

Modify the client: the browser manual and automatic proxy configuration;

Modify the network: It is intercepted by a switching device and a routing device that monitors HTTP traffic and imports traffic to an agent;

To modify the DNS namespace:

Modify Web server: HTTP redirection

HTTP (ii) proxy