Open proxy 769273 226035802 2008-07-16T15:20:45Z Gyrofrog 52387 /* Advanteges */ sp. {{dablink|For Wikipedia's policy on editing from open proxies, please see [[Wikipedia:Open proxies]].}} An '''open proxy''' is a [[proxy server]] which is accessible by any [[Internet]] user. Generally, a proxy server allows users within a network group to [[store and forward]] internet services such as [[Domain Name System|DNS]] or [[web page]]s so that the [[Bandwidth (computing)|bandwidth]] used by the group is reduced and controlled. With an "open" proxy, however, any user on the Internet is able to use this forwarding service. ==Advantages== By using some open proxies (the so-called "anonymous" open proxies), users can conceal their true [[IP address]] from the accessed service, and this is sometimes used to abuse or interrupt that service, potentially violating its [[terms of service]] or some laws; open proxies are therefore often seen as a problem. However, anonymous open proxies are also used to increase anonymity or security when browsing the web or using other internet services: a user's true IP address can be used to deduce information about that user and to [[hacker (computer security)|hack]] into his or her computer. Furthermore, open proxies can be used to circumvent efforts at [[Internet censorship]] by governments or organizations. Several web sites exist which provide constantly updated lists of open proxies.<ref>[http://dmoz.org/Computers/Internet/Proxying_and_Filtering/Hosted_Proxy_Services/Free/Proxy_Lists/ List of sites that provide lists of open proxies]</ref> ==Disadvantages== It is possible for a computer to be running an open proxy server without knowledge of the computer's owner. This can be the result of misconfiguration of proxy software running on the computer, or of infection with [[malware]] ([[computer virus|viruses]], [[trojan horse (computing)|trojans]] or [[computer worm|worms]]){{Fact|date=July 2008}} designed for this purpose. Many open proxies run very slowly, sometimes below 14.4 [[kbit/s]], or even below 300 bit/s, while other times the speed may change from fast to slow every minute. Some, such as [[PlanetLab]] proxies, run faster and were intentionally set up for public use. {{Fact|date=July 2008}} Because open proxies are often implicated in abuse, a number of methods have been developed to detect them and to refuse service to them. [[Internet Relay Chat|IRC]] networks with strict usage policies automatically test client systems for known types of open proxies.<ref>[http://www.blitzed.org/bopm/ Blitzed Open Proxy Monitor]</ref> Likewise, a [[mail transport agent|mail server]] may be configured to automatically test mail senders for open proxies, using [[software]] such as <CODE>proxycheck</CODE>.<ref>[http://www.corpit.ru/mjt/proxycheck.html proxycheck: Open Proxy checker]</ref> Increasingly, mail servers are configured out of the box to consult various [[DNSBL]] servers in order to block spam; some of those DNSBLs also list open proxies. ==Closed proxy== A closed proxy is one that is only accessible to specific individuals. It is possible to use someone else's computer in order to hide one's identity and/or location. == References == <references/> ==See also== * [[Open mail relay]], a server that allows anyone to forward email messages, often used for spamming. [[Category:Computer network security]] [[de:Proxy_(Rechnernetz)]] [[es:Proxy#Proxy_Abierto]] [[ko:공개 프록시]] [[ja:公開プロキシ]] [[no:Åpen proxy]] [[nn:Open mellomtenar]] [[pl:Open proxy]] [[ru:Открытый прокси]] [[simple:Open proxy]] [[fi:Avoin välityspalvelin]] [[vi:Proxy mở]] [[yi:אפענער פראקסי]]