A proxy is a server that acts as an intermediary between an end device, such as a computer, and the Internet. When a device establishes an Internet connection via a proxy server, the proxy sends the requests to the target server and forwards the responses back to the end device.
What does a proxy server do?
A proxy server can have different functions. For example, it can hide the user’s IP address, which increases their anonymity on the Internet. Because it acts as a middle point on the connection, websites and services only recognize the IP address of the proxy and not that of the original user. It can also act as a security filter to block malicious traffic before it reaches a company’s network or an end device.
In corporate networks, proxies are often used to regulate Internet access and control which websites and services employees can use. Similarly, a proxy with a location in a specific country can be used to bypass regional restrictions and censorship.
Finally, proxies can cache frequently requested data to improve loading speed and reduce bandwidth usage by eliminating the need to reload identical content each time.
How does a proxy server work?
If a user wants to access a website or resource on the Internet, their device first sends a request to the proxy server. Instead of the user’s device sending it directly to the target website, the proxy receives the request and forwards it on their behalf. It then can change the request data during this stage, such as hiding the user’s IP address to maintain anonymity.
If the proxy server has already processed a similar request before and has cached the requested data, it can send this data directly back to the user without forwarding the request. This improves the loading speed and reduces bandwidth usage.
If the proxy has not cached the data, it forwards the request to the relevant website or service. The target website processes the request and sends a response back to the server. The proxy server receives the response from the target website.
It can check and modify this response (for example, removing advertising or performing security checks) before forwarding it to the user device. The user receives the response as if it had come directly from the website, even though it was actually transmitted by the proxy server.
What types of proxy servers are there?
There are different types of proxy servers with different levels of data protection. Each type of proxy has specific use cases and offers different degrees of anonymity, security and functionality. Examples of such types include:
- Transparent proxies forward requests without changing or hiding the user’s IP address. They are transparent because the end server can see the user’s true IP address. They are used, for example, in companies and educational institutions for content filtering and caching.
- Anonymous proxies hide the user’s IP address from the target servers. They are useful for users who wish to remain anonymous. However, complete anonymity is not guaranteed, as the proxy itself knows the original IP address.
- Distorting proxies pass a false IP address to the destination site, which makes them a step above anonymous proxies. They are used to bypass geo-location restrictions and provide higher anonymity.
- High-anonymity (elite) proxies offer the highest level of anonymity. They hide both the fact that a proxy is being used and the user’s original IP address. They are suitable for users who want to keep their online activities completely private.
- Reverse proxies stand in contrast to most other proxy types because they are used on the server side. They forward requests to one or more servers and can be used for load balancing, caching, SSL encryption and as a security measure.
- SOCKS proxies are anchored deeper in the network layer and are not limited to HTTP traffic but can transmit any type of network traffic. SOCKS proxies are popular for applications that require a higher level of security or firewall bypassing .
What are the advantages and disadvantages?
The use of proxy servers can have advantages and disadvantages. The choice of whether a proxy server should be used (and what type to implement) depends heavily on the specific requirements, context and security needs.
- Proxies can serve as a security barrier by preventing direct access to a network and filtering potentially harmful traffic.
- They can hide the user’s IP address, which increases anonymity and makes it more difficult to track online activity.
- With a proxy server in another country, users can bypass regional restrictions and access content that may not be available in their own country.
- Proxies can cache frequently requested resources, which reduces load times for repeated requests and reduces bandwidth usage.
- In corporate environments, proxies enable monitoring and control of employee Internet access, which can help enforce policies and prevent inappropriate usage.
- The additional processing and forwarding by the proxy can reduce Internet speed, especially if the proxy server is overloaded or geographically distant.
- A poorly configured or insecure proxy can pose a security risk because all traffic is routed through it. This can lead to data breaches if the server is compromised.
- Some proxies do not fully encrypt traffic, which can lead to security breaches, especially for sensitive data.
- Not all applications and services support the use of proxies, leading to connectivity or functionality problems.
- Some proxies, especially transparent and simple anonymous proxies, do not offer complete anonymity as they may reveal information about the origin of the request.