proxy server

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proxy server

Computing a computer that acts as an intermediary between a client machine and a server, caching information to save access time

proxy server

[′präk·sē ‚sər·vər]
(computer science)
Software for caching and filtering Web content to reduce network traffic on intranets, and for increasing security by filtering content and restricting access.

Proxy Server

(software, security)
Microsoft's proxy server and proxy gateway, designed to provide extensible firewall and network security. Proxy Server is part of BackOffice.

proxy server

(programming, World-Wide Web)
A process providing a cache of items available on other servers which are presumably slower or more expensive to access.

This term is used particularly for a World-Wide Web server which accepts URLs with a special prefix. When it receives a request for such a URL, it strips off the prefix and looks for the resulting URL in its local cache. If found, it returns the document immediately, otherwise it fetches it from the remote server, saves a copy in the cache and returns it to the requester. The cache will usually have an expiry algorithm which flushes documents according to their age, size and access history.

Compare proxy gateway.

proxy server

A proxy server is a computer system or router that functions as a relay between client and server. They help prevent an attacker from invading a private network and are one of several tools used to build a firewall.

The word proxy means "to act on behalf of another," and a proxy server acts on behalf of the user. All requests to the Internet go to the proxy server first, which evaluates the request and forwards it to the Internet. Likewise, responses come back to the proxy server and then to the user.


Proxy Servers Provide Anonymity
Like a virtual private network (VPN), a proxy server hides the user's IP address when accessing the Internet. See VPN and TLS.







Address Translation and Caching
The proxy server is a dual-homed host with two network IP addresses. The address on the outbound side is the one the Internet sees. Proxies are often used in conjunction with network address translation (NAT), which hides the users' IP addresses on the internal network. Proxy servers may also cache Web pages so that the next request for that page can be retrieved much faster. See NAT and proxy cache.

Other Proxies
Anonymous proxy servers let users surf the Web and keep their IP address private (see anonymous proxy). Although not specifically called proxies, Internet email (SMTP) and the Usenet new system (NNTP) are somewhat similar because messages are relayed from sender to recipient. See firewall.

Application Level and Circuit Level
"Application-level" proxies or "application-level gateways" are dedicated to specific content such as HTTP (Web) and FTP (file transfer). In contrast, a "circuit-level" proxy supports every application (see SOCKS).

Forward and Reverse Proxies
In this definition, the proxy servers are "forward proxies" that hide the details of the clients from the servers. However, proxies can also reside at the website to hide details from the clients (see reverse proxy).


A Proxy Server in a LAN
In this example, the proxy server resides between two routers in the "demilitarized zone." See DMZ.
References in periodicals archive ?
Prosecutor Kursat Kayral asked the Telecommunication and Communication Authority (TIB), a government body that oversees internet accessibility in the country, whether there was proxy sites enabling access to the YouTube.
And all the while the PTA has been hot on the trail, shutting down proxy sites as soon as they are discovered.
With anti-filtering software and the use of web proxy sites, some Iranians have been able to circumvent those controls to browse YouTube, Facebook, Twitter and Farsi-language news sites that were blocked.
One constant challenge districts face is to stay on top of the hundreds of thousands of proxy sites that allow students to elude filters.
Not to be confused with traditional URL blacklists, eSoft's SiteFilter technology goes beyond blocking porn and gambling by dynamically classifying online threats like malware distribution, phishing and proxy sites.
Some Iranians use so-called proxy sites or antifiltering search engines to access websites that have been blocked by the government, in turn further slowing the already slow Internet speeds.
To ensure that blocklists are kept current and legally compliant, it offers automatic daily updates from the Internet Watch Foundation and screens the actual content and construction of Web pages in detail, detecting and blocking objectionable material, dangerous hidden content and proxy sites.
Administrators can block the usage of anonymous proxy sites that are often used to bypass safeguards.
Beginning early this year, however, access even to obscure proxy sites began to be blocked, often within a few minutes of a successful connection.
Until recently, the approach to optimizing a website across different devices was to create separate proxy sites for mobile and tablet," said Patrick Collins, President of 5th Finger.
uk/news/technology-18518777) BBC that more proxy sites had been made available "within minutes".
With an increasing number of anonymous proxy sites now being access via HTTPS, the latest version of Tru-View Technology is now also able to identify and block these in real-time offering enhanced protection against anonymous proxies and allow IT managers to continue to provide a secure environment.