An open proxy is a proxy server which is accessible by any Internet user. This article or section does not cite its references or sources. ...

Generally, a proxy server allows users within a network group to store and forward internet services such as DNS or web pages so that the 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. Store and forward is a communications technique in which messages are sent to a intermediate station where they are kept and sent at a later time to the final destination or to another intermediate station. ... The domain name system (DNS) stores and associates many types of information with domain names, but most importantly, it translates domain names (computer hostnames) to IP addresses. ... A screenshot of a web page. ... This article or section does not cite its references or sources. ...

By utilizing 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 the law; 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 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.^[1] An IP address (Internet Protocol address) is a unique address that devices use in order to identify and communicate with each other on a computer network utilizing the Internet Protocol standard (IP)—in simpler terms, a computer address. ... In computing and telecommunication networks (including of course the Internet) terms of service or ToS is an agreement under which a service provider agrees to provide services to the users of the service. ... Hacker in a security context refers to a type of computer hacker who is involved in computer security/insecurity and is able to exploit systems or gain unauthorized access through skills, tactics and detailed knowledge. ... Countries where the free flow of information is restricted. ...

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 (viruses, trojans or worms) designed for this purpose. Malware or malicious software is software designed to infiltrate or damage a computer system without the owners informed consent. ... A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. ... In the context of computer software, a Trojan horse is a program that contains or installs a malicious program (sometimes called the payload or trojan). The term is derived from the classical myth of the Trojan Horse. ... A computer worm is a self-replicating computer program. ...

Many open proxies run very slowly, sometimes below 14400 baud (14.4 Kbps), or even below 300 baud, 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. In telecommunications and electronics, baud (pronounced , unit symbol Bd), is a measure of the symbol rate; that is, the number of distinct symbol changes (signalling events) made to the transmission medium per second in a digitally modulated signal. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... PlanetLab is a group of computers available as a testbed for networking and distributed systems research. ...

Because open proxies are often implicated in abuse, a number of methods have been developed to detect them and to refuse service to them. IRC networks with strict usage policies automatically test client systems for known types of open proxies.^[2] Likewise, a mail server may be configured to automatically test mail senders for open proxies, using software such as proxycheck.^[3] 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. Internet Relay Chat (IRC) is a form of real-time Internet chat or synchronous conferencing. ... A mail transfer agent or MTA (also called a mail server, or a mail exchange server in the context of the Domain Name System) is a computer program or software agent which transfers electronic mail messages from one computer to another. ... Computer software (or simply software) refers to one or more computer programs and data held in the storage of a computer for some purpose. ... A DNSBL is a means by which an Internet site may publish a list of IP addresses that some people may want to avoid and in a format which can be easily queried by computer programs on the Internet. ...

References

• Free High speed open proxy to bypass firewall

1. ^ List of sites that provide lists of open proxies
2. ^ Blitzed Open Proxy Monitor
3. ^ proxycheck: Open Proxy checker

See also

• Open mail relay, a server that allows anyone to forward email messages, often used for spamming