What Is an Open Proxy Server?

An open proxy is a proxy server that can be accessed by all Internet users. In general, a proxy server (such as a closed proxy) only allows users of a specific domain to use this proxy to save and forward to Internet services such as DNS or web pages, with the goal of reducing and controlling the traffic used by this group. However, the use of open proxy enables any user to use this forwarding service.

Anonymous open proxy is a way to help computer users hide their

Running an open proxy server may be done without the owner of the computer being aware of it. This can be caused by a misconfiguration of the proxy software on the computer, or it can be dedicated to this purpose.

Because open agents are often associated with abuse, many methods have been developed to identify them and refuse to provide them with services. An IRC network with strict usage guidelines will automatically test if the client is a known open proxy. Similarly, the mail server can be configured with software such as proxycheck to automatically test whether the sender is an open proxy. Because open proxies are often difficult to track, they are useful for those who need online anonymity and privacy protection.

Some IRC groups and mail servers run DNSBL to expose the IP addresses of known open proxies, such as AHBL, CBL, NJABL, and SORBS.

The automatic testing of open proxy clients is ethically controversial. Some experts, such as Vernon Schryver, believe that such tests are a "very bad approach." Others believe that such detection of the client is reasonable for services that include this content in the terms of service. ^[2]