A proxy server is a computer that sits between a client and a server to intercept requests. There are several uses for a proxy server, but the most common is to speed up network traffic by caching frequently requested pages or files. By doing this, the server can deliver the request quickly, only polling the server when necessary. In this way, it not only speeds up network traffic, but also relieves the load on the server. Dozens of proxy servers are used by major Internet Service Providers (ISPs) and hubs.
An https proxy is more secure than an http proxy.
Filtering or censoring is another use of a proxy server. A company that provides Internet connectivity to its employees can configure this server to block requests from certain websites. You can also filter content based on configurable criteria to help enforce acceptable use policies.
Some proxy servers encrypt IP addresses.
If a proxy server does not require a web browser to be configured to use the proxy, it is called a transparent proxy. Otherwise, the web browser must point to the proxy to use it. Companies prefer the former, as employees cannot prevent it by resetting their web browsers. These types of servers are also commonly used as firewalls. They can scan for malware, viruses and other threats, protecting the main server and the network.
Secure Sockets Layer (SSL) servers used to create virtual private networks (VPNs) sometimes use HTTP proxies. These proxies speed traffic through secure channels and scan tunneled communications for viruses. The http proxy server can encrypt, decrypt and cache encrypted data. Normal proxy servers cannot cache encrypted data for security reasons and are therefore not suitable for a VPN. There are differences of opinion as to whether http proxies create potential security risks.
Yet another use for a proxy server is to provide anonymous web browsing. Many services provide proxies for the public to use to protect their anonymity online. Requests from the client go to the website’s proxy server, which removes the client’s Internet Protocol (IP) address and forwards them. The information is routed back to the proxy, which then forwards the pages to the client’s browser. As far as the Internet is concerned, the only IP address on the remote server is the proxy IP address. Only the proxy knows the IP address of the client. Companies that run anonymous proxy servers often claim to frequently clear server logs to protect customer privacy.
Another model includes a network of volunteer proxy servers. This model uses encryption to obfuscate the original IP address and the final path that a request follows. As the request progresses through the Internet from one proxy server to the next, each intermediate server can only read adjacent steps in the chain. Content, origin and final destination are not available.
The server end decrypts the content and hands the request to the server without a plain text record of where the request originated from. The page or file returns the same way, through a series of encrypted steps. This system prevents traffic analysis and protects privacy while protecting the proxy servers themselves.
