A proxy server is an intermediary computer that is between the user’s computer and the Internet. It is commonly used by ISP’s with slow connections or heavy loads. A proxy server has a variety of potential purposes, including:
To keep machines behind it anonymous, mainly for security.
To speed up access to resources (using caching). Web proxies are commonly used to cache web pages from a web server
To apply access policy to network services or content, e.g. to block undesired sites.
To access sites prohibited or filtered by your ISP or institution.
To log / audit usage, i.e. to provide company employee Internet usage reporting.
To bypass security / parental controls.
To circumvent Internet filtering to access content otherwise blocked by governments.
To scan transmitted content for malware before delivery.
To scan outbound content, e.g., for data loss prevention.
To allow a web site to make web requests to externally hosted resources (e.g. images, music files, etc.) when cross-domain restrictions prohibit the web site from linking directly to the outside domains.