What is an Open Proxy?


Open proxies, also known as public proxies, are types of proxies that enable users to connect to and use the proxy without having to provide authentication. Open proxies can be configured on computers or networks that have opened the required ports and have the necessary proxy software to provide proxy access. It allows Internet traffic to pass through the open proxy.

How does an open proxy work?

Proxy servers normally require users to authenticate themselves or to connect from a specific network address to use the service. An open proxy server does not have this requirement and lets anyone on the Internet to connect to the proxy’s computer. When a web browser has been configured to use an open proxy server, requests are sent to the proxy server before going to the Internet.

Open Proxy server diagram

This results in a sense of anonymity as the destination server will see the proxy’s information, rather than the information of the user’s personal network. Data returned from the Internet also goes through the proxy server before being forwarded to the user’s computer.

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What is the use of an open proxy?

There are a number of reasons why users use open proxy servers. An Internet user may, for example, want to hide their identity while downloading files, visiting websites, using chat rooms, or posting on message boards.

Another use is to access a website that is blocked on local networks. The proxy server can access websites that the user’s computer is not able to access directly. Proxy servers also support caching and this might improve performance while surfing. It is most useful when the data the user needs to access is stored on the proxy server.

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Types of open proxies

Open proxies usually refer to HTTP proxies or SOCKS proxies that can be found on proxy lists. However, web proxies can also be seen as open as they do not require authentication and they can be accessed without restrictions.

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Where to find open proxies?

There are plenty of open proxies listed in proxy lists. A Google search on “proxy list,” “HTTP proxy,” “open proxy list” will show tens of thousands of results. My recommendation is to start with the proxy lists from my Proxy Tools page. And here is a quick guide on how to choose an open proxy:

  1. Open the proxy list site.
  2. Choose the location of the proxy (e.g., Germany).
  3. Select a high anonymous proxy/elite proxy. In my opinion, an anonymous proxy is a must as it hides your real IP address and it provides better privacy and anonymity.
  4. Choose the one with maximum speed, minimum latency and highest uptime (if such info is presented).

How to choose an open proxy?

Important note: do NOT use an open proxy with sensitive personal data (credit card info, username/passwords, personal social media accounts, etc.).

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Advantages of open proxies

Anonymous open proxies (implemented as elite proxies) are useful for those wanting online privacy and anonymity. It helps users hide their IP addresses from web servers, as it appears as if the server requests come from the proxy server. It makes it more difficult to reveal their identity and assists in preserving their perceived security while using internet services or browsing the web.

Extensive internet security and real anonymity may not be achieved by this method alone, because website operators are able to use client-side scripts to find the browser’s real IP address. Open proxies may also keep logs of all connections.

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Disadvantages of open proxies

It is possible that a computer runs as an open proxy server without its owner being aware of this. It can happen when proxy software running on the computer is misconfigured, or from a malware infection designed for this purpose.

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How do abusers use open proxies

There are numerous ways in which abusers use open proxies:

Comment / Forum Spamming

This is done by mass-posting of “comments” in forums, blogs, guest books, and any other site that allows open interaction by users. Comments typically include the “spam advertisements” ranging from pharma, porn, pay-per-click affiliates, and gambling. The other type is SEO (Search Engine Optimisation) where the comments include a link back to a page they are trying to increase search engine rankings for.

Distributed Brute-Forcing

This is repeated attempts to try username/password combinations to obtain unauthorized access to an account. As target sites identify brute-forcing activities, the source IP address is blocked from further attempts. The brute-force attempts are therefore distributed between various open proxies to change the source IP addresses of the attempt.

IRC/ICQ masking

Users of chat networks often want to hide their IP address, sometimes because they are engaged in illegal activities (e.g., selling stolen identities), or because they want to stay anonymous in case a flame war breaks out and is followed by a denial of service attack.

Pay-to-click (PTC) “Cheating”

Pay-to-read, pay-to-promote and pay-to-click sites are businesses that have different degrees of legitimacy. It is unlikely that site owners or members pay taxes. Site owners may also not pay out their members, and the members often try to “cheat” the sites by using infected machines and botnets.

Other browsing and site scraping

This category can include some things, including regular page scraping, “not safe for work” (NSFW) surfing, porn and general browsing. Based on transaction timestamps in logs, a significant percentage of porn surfing seems to be the automated scraping of images.

Proxy testing / Reveal host IP

Open proxies are also often used to analyze traffic coming from automated checks to recognize open proxies. When a proxy is connected, it is tested to determine which IP address is exposed on the Internet by the proxy.

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Conclusion

Open proxies are often used for hiding users’ identity while they download files, visit websites, use chat rooms, or post on message boards, and also for accessing websites that are blocked on local networks. They can also improve performance while surfing. Open proxies do however not offer strong privacy and anonymity protection and are often used for nefarious purposes.