Function of a Proxy Server Essay Example
FUNCTIONS OF A PROXY SERVER
A proxy server has a large 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 log / audit usage, i.e. to provide company employee Internet usage reporting.
• To bypass security/ parental controls.
• To scan transmitted content for malware before delivery.
• To scan outbound content, e.g., for data leak protection.
• To circumvent regional restrictions.
Proxy servers implement one or more of the following functions:
Caching proxy server a caching proxy server accelerates service requests by retrieving content saved from a previous request made by the same client or even other clients. Caching proxies keep local copies of frequently requested resources, allowing large organizations to significantly reduce their upstream bandwidth usage and cost, while significantly increasing performance. Most ISPs and large businesses have a caching proxy. These machines are built to deliver superb file system performance (often with RAID and journaling) and also contain hot-rodded versions of TCP. Caching proxies were the first kind of proxy server.
The HTTP 1.0 and later protocols contain many types of headers for declaring static (cacheable) content and verifying content freshness with an original server, e.g. ETAG (validation tags), If-Modified-Since (date-based validation), Expiry (timeout-based invalidation), etc. Other protocols such as DNS support expiry only and contain no support for validation.
Some poorly-implemented caching proxies have had downsides (e.g., an inability to use user authentication). Some problems are described in RFC 3143 (Known HTTP Proxy/Caching Problems).
Web proxy
A proxy that focuses on WWW traffic is called a "web proxy". The most
A proxy server has a large 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 log / audit usage, i.e. to provide company employee Internet usage reporting.
• To bypass security/ parental controls.
• To scan transmitted content for malware before delivery.
• To scan outbound content, e.g., for data leak protection.
• To circumvent regional restrictions.
Proxy servers implement one or more of the following functions:
Caching proxy server a caching proxy server accelerates service requests by retrieving content saved from a previous request made by the same client or even other clients. Caching proxies keep local copies of frequently requested resources, allowing large organizations to significantly reduce their upstream bandwidth usage and cost, while significantly increasing performance. Most ISPs and large businesses have a caching proxy. These machines are built to deliver superb file system performance (often with RAID and journaling) and also contain hot-rodded versions of TCP. Caching proxies were the first kind of proxy server.
The HTTP 1.0 and later protocols contain many types of headers for declaring static (cacheable) content and verifying content freshness with an original server, e.g. ETAG (validation tags), If-Modified-Since (date-based validation), Expiry (timeout-based invalidation), etc. Other protocols such as DNS support expiry only and contain no support for validation.
Some poorly-implemented caching proxies have had downsides (e.g., an inability to use user authentication). Some problems are described in RFC 3143 (Known HTTP Proxy/Caching Problems).
Web proxy
A proxy that focuses on WWW traffic is called a "web proxy". The most