An open proxy is a type of proxy server that is accessible by any

Internet The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...

user. Generally, a proxy server only allows users within a network group (i.e. a closed proxy) to store and forward Internet services such as DNS or

web page A web page (or webpage) is a World Wide Web, Web document that is accessed in a web browser. A website typically consists of many web pages hyperlink, linked together under a common domain name. The term "web page" is therefore a metaphor of pap ...

s to reduce and control the bandwidth used by the group. With an open proxy, however, any user on the Internet can use this forwarding service.

Advantages

An anonymous open proxy is useful to those looking for online anonymity and privacy, as it can help users hide their

IP address An Internet Protocol address (IP address) is a numerical label such as that is assigned to a device connected to a computer network that uses the Internet Protocol for communication. IP addresses serve two main functions: network interface i ...

from web servers since the server requests appear to originate from the proxy server. It makes it harder to reveal their identity and thereby helps preserve their perceived security while browsing the web or using other internet services. Real anonymity and extensive

internet security Internet security is a branch of computer security. It encompasses the Internet, browser security, web site security, and network security as it applies to other applications or operating systems as a whole. Its objective is to establish rules ...

might not be achieved by this measure alone as website operators can use client-side scripts to determine the browser's real IP address and the open proxy may be keeping logs of all connections. Open proxies also do not stop tracking cookies and fingerprinters from identifying users. Most public VPNs work through open proxies.

Disadvantages

It is possible for a computer to run as an open proxy server without the computer's owner knowing it. This can result from misconfiguration of proxy software running on the computer, or from infection with

malware Malware (a portmanteau of ''malicious software'')Tahir, R. (2018)A study on malware and malware detection techniques . ''International Journal of Education and Management Engineering'', ''8''(2), 20. is any software intentionally designed to caus ...

(

viruses A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almo ...

, trojans or

worms The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive catalogue and list of names of marine organisms. Content The content of the registry is edited and maintained by scien ...

) designed for this purpose. If it is caused by malware, the infected computer is known as a zombie computer.

Testing for access from an open proxy

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 IRC (Internet Relay Chat) is a text-based chat system for instant messaging. IRC is designed for group communication in discussion forums, called '' channels'', but also allows one-on-one communication via private messages as well as chat ...

networks with strict usage policies automatically test client systems for known types of open proxies. Likewise, a mail server may be configured to automatically test mail senders for open proxies, using

software Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications. The history of software is closely tied to the development of digital comput ...

such as proxycheck. Groups of IRC and electronic mail operators run

DNSBL A Domain Name System blocklist, Domain Name System-based blackhole list, Domain Name System blacklist (DNSBL) or real-time blackhole list (RBL) is a service for operation of mail servers to perform a check via a Domain Name System (DNS) query w ...

s publishing lists of the

es of known open proxies, such as

AHBL The Abusive Hosts Blocking List (AHBL) was an internet abuse tracking and filtering system developed by The Summit Open Source Development Group, and based on the original Summit Blocking List (2000–2002). Its DNSBLs were shut down on Jan 1, 2 ...

, CBL,

NJABL Not Just Another Bogus List (NJABL) was a DNS blacklist. NJABL maintained a list of known and potential spam sources ( open mail relays, open proxies, open form to mail HTTP gateways, dynamic IP pools, and direct spammers) for the purpose of bei ...

(till 2013), and

SORBS Sorbs (; ; ; ; ; also known as Lusatians, Lusatian Serbs and Wends) are a West Slavs, West Slavic ethnic group predominantly inhabiting the parts of Lusatia located in the German states of Germany, states of Saxony and Brandenburg. Sorbs tradi ...

(in operation since 2002). The AHBL discontinued public access in 2015.

References

{{Reflist Internet security Proxy servers es:Proxy#Proxy Abierto pt:Proxy#Proxy abreto

Advantages

Disadvantages

Testing for access from an open proxy

See also

References