Proxy Server

A proxy server is a computer that can be connected as an interface between two computers or networks. It takes over an intermediary function, by receiving requests and passing them on with its own IP address to another network. Proxy servers can be used on the Internet in order to conceal one’s IP address.


The basic meaning of the word “proxy” is the agency, function, or office of a deputy who acts as a substitute for another (Merriam Webster English dictionary. A proxy server thus acts like a substitute for another.

Internet or network solution[edit]

Proxy servers are used for both the Internet and proprietary networks. In principle, anyone can set up their own proxy server.

Network proxy[edit]

A proxy server can also be used as part of a network. Files or requests can be exchanged between two communication partners without the respective actual network address being transmitted. A connection can also be established when both network addresses are not compatible.

Dedicated proxy[edit]

A dedicated proxy not only connects two communication partners; it also has a direct effect on the form of communication. It can manipulate, filter or cache the data packets sent to it. Caching is applied a lot especially on the Internet. That way, the requested files are available more quickly to the Internet user. For data transmission, the dedicated proxy can read and apply various protocols such as http or ftp.

Circuit level proxy[edit]

A circuit level proxy is typically installed on a firewall. It operates independently of the network protocol as a filter for traffic from specific addresses or ports. Thus, the generic proxy, as it is also called, can request authentication for the use of a website.


Proxy servers have multiple functions. The most common ones are briefly explained below.

  • Interface between the home network and the public network: You can access a public website through a proxy. This system is often used by universities. The students can access the university network and download e-Media or view it at home or on the go via a proxy server. The use of a proxy provides additional protection against unwanted network access.
  • Control of network bandwidth: By using a proxy, a webmaster can control the network traffic. Users and user groups are allocated only certain resources. The control tasks also include monitoring of server availability.
  • Protection against network attacks: The proxy server is placed between the actual data server and the users. Websites that work with sensitive customer data, such as online stores often use this solution to protect their servers.
  • Network logging: Proxy servers are commonly used for logging of network activity. Harmful access can be identified more quickly that way.
  • Anonymization of traffic: Internet users often use proxy services to anonymize their own IP address. That way restrictions on the use of a website can be evaded and the webmaster of the website which is accessed with a proxy will not be able to determine the actual sender of the request from the IP.
  • Intermediate storage in order to reduce the server load: a proxy server can store requests that have been sent to it. Since there are server requests, especially in Internet usage, which are repeated, the proxy can deliver the requested information without causing a load for the actual server. At the same time, the requesting agent receives information faster.
  • Blocking of content: In public networks, access to the Internet can be blocked through an upstream proxy server. In their home network, parents can prevent their children getting directed to websites with pornographic or racist content while surfing. Proxy servers are also used in some repressive countries to censor the Internet for the population. The filter functions of a proxy may also include the removal of interfering advertising while surfing.

Relevance to search engine optimization[edit]

SEOs can take advantage of proxies in their work. However, proxy servers are sometimes also used for black hat techniques.

  • Page visits: For search engine optimization, the use of proxy servers has the advantage that search engines cannot draw any conclusions on common server requests. This is mainly used for automated site queries such as for SERP rankings, so that the IP address of the user doesn’t get blocked due to the many requests.
  • Reverse IP proxy: This type of IP manipulation is used by SEOs as a black hat technique to give their projects different virtual Class C networks and IP addresses. In fact, all websites are located on one server. The proxy issues different IPs and Class C networks for requests from networks.
  • Spamming: Proxy servers are also often used to send spam requests or spam comments in blogs. Thus, the blocking of the IP is prevented because the spammer cannot be recognized.
  • Analysis of user behavior: Proxy servers can complicate the analysis of website traffic. Thus, it is possible for a German online store to get a lot of traffic from overseas or Eastern European countries. This association can be made, because a lot of visitors to the site use a proxy server, and it transmits an IP address from those regions to the server. This “wrong” IP address is then stored in the log file.