What is a proxy server?
Put most simply, a proxy is “a server that sits between a client application, such as a Web browser, and a real server. It intercepts all requests to the real server to see if it can fulfill the requests itself. If not, it forwards the request to the real server.” (from the Webopedia definition). For more information on what the proxy server does, see this Powerpoint Presentation on the Medical Library Proxy Server by Mark Gentry, Clinical Support Librarian (requires MS Powerpoint 97 or 2000, or the Powerpoint Viewer).
A proxy server usually serves multiple roles: it always acts as a security device, and its optional functions are as a network management tool and/or a performance enhancement subsystem. At its simplest, a proxy server accepts requests from one or more computers and relays those requests to other computers to screen and/or control the access of PCs on an internal network to services on the Internet.
is a server (a computer system or an application program) that acts as a go-between for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource, available from a different server. The proxy server evaluates the request according to its filtering rules. For example, it may filter traffic by IP address or protocol. If the request is validated by the filter, the proxy provides the resource by connecting to the relevant server and requesting the service on behalf of the client. A proxy server may optionally alter the client’s request or the server’s response, and sometimes it may serve the request without contacting the specified server. In this case, it ‘caches’ responses from the remote server, and returns subsequent requests for the same content directly.
A proxy server is a server that acts as an intermediary between a workstation user and the Internet. When a user connects to the proxy server and requests an online service, such as a file or a web page, available from a different server, the proxy server connects to the specified server and requests the service on behalf of the user. While proxy servers exist for most Internet protocols, the best known are Web Proxy Servers, also known as HTTP Proxy Servers from the official name of the Web protocol. Proxies can be transparent (part of the Internet connection requiring no additional user configuration), or require access to specific URLs, or configured in the web browser.
A proxy server is a computer running software which allows it to operate as a “middle-man” between a workstation on a network and the Internet. The proxy server relays information between a workstation and an Internet site. In effect, the server in this situation is acting as a “proxy” for the workstation. Proxy servers are commonly used to improve performance for web users by temporarily caching webpages and to provide remote access to licensed resources by relaying requests from authorized remote users through the IP of the proxy. Proxy servers can also be used to log Internet use and block access to prohibited sites. One result of connecting to an Internet resource through a proxy server is that the destination resource or website cannot identify the address of the originating workstation – only the IP of the proxy server is apparent.
