Knowledge What Is a Proxy Server? An Easy-to-Understand Explanation of How It Works, Its Types, Benefits, and Points to Note for Beginners

A proxy server is a server that sits between user devices (PCs and smartphones) and the Internet and relays communications. The word “proxy” means “agent” or “substitute”, and accordingly it connects to the Internet on behalf of your device.

Normally, when we browse a website, our device sends a request directly to the web server and receives information in return. When using a proxy server, however, the request is first sent to the proxy server, which then accesses the target web server. The proxy server functions as a middleman that returns the received information to the device. This mechanism provides benefits such as enhanced security, more efficient communication, and access control.

Internal networks in companies and other organizations are protected by firewalls to guard against external threats. Because firewalls block unauthorized communication, their settings may prevent direct access to the Internet from inside the network.
To address this, a proxy server is installed between the internal LAN and the Internet, and only specific types of communication are allowed through, enabling safe Internet access.

A proxy server stands between the client (the user’s device) and the web server, acting as an intermediary for communication. This mechanism provides benefits that cannot be obtained with direct communication, such as enhanced security, more efficient traffic, and access control.

When you enter a website’s URL in your browser, the request is first sent to the proxy server. After receiving the request, the proxy server accesses the target web server on behalf of the client. From the web server’s point of view, the access is coming from the proxy server, not from the user’s device.

The web server responds to the request by returning website data to the proxy server. The proxy server receives that response, performs security checks and content filtering as needed, and then forwards only safe data to the user’s device. In this way, a website is delivered for display to the user.

By using a proxy server, you can enjoy many benefits, including improved security and more efficient communication.

When accessing the Internet through a proxy server, the destination web server records the proxy server’s IP address instead of the user’s. Because an IP address is like an address on the Internet, hiding it makes it harder to pinpoint where the access originated. This increases anonymity and reduces the risk of direct attacks and unauthorized access.

Proxy servers have a caching function that temporarily stores data from websites that have already been accessed. When someone else on the same network tries to access a site that has already been viewed, the proxy server does not need to retrieve the data from the original web server; instead, it returns the stored cache. This speeds up website display and reduces network load.

By standing between the internal network and the Internet and mediating communications, proxy servers help strengthen security. Security-enabled proxy servers can block unauthorized external communications and check whether data sent from web servers contains viruses or malware. They can also use authentication functions to restrict which users are allowed access, helping prevent internal information leaks.

Proxy servers can centrally manage records of the traffic that passes through them (access logs). This makes it possible to determine “who” accessed “which websites” and “when”. Log information can be used to restrict access to non-work-related sites and to investigate the cause of cyberattacks when they occur. Combined with authentication functions, it is extremely effective for strengthening IT governance within companies.

Despite their many advantages, there are also some disadvantages and points to be careful about when using proxy servers.

Some proxy servers are malicious and aim to steal information from users. In particular, “open proxy servers”, which anyone can use for free, are often offered by unknown providers and may eavesdrop on your communications or redirect you to fake websites. Caution should be used regarding such services.

While caching can speed up communication in some cases, all traffic must pass through the proxy server, which may make communication slower than usual under certain conditions. Possible causes include the processing capacity of the proxy server, network congestion, or using a proxy server located far away geographically.

To use proxy servers safely, the most important thing is to choose services operated by trusted providers. It is recommended either to build and operate servers in-house or to use paid proxy services provided by reputable specialists. Since misconfiguration can create security holes, specialized knowledge is required for deployment and operation.

Proxy servers are broadly divided into two types depending on where they are installed and their purpose: “forward proxies” and “reverse proxies”.

When people speak of a proxy server, they are usually referring to a forward proxy. It is installed on the client (user) side of the network and accesses servers on the Internet as an intermediary on behalf of the client. Its main purposes are to enhance anonymity, speed up website display through caching, and control access from internal networks.

Unlike forward proxies, which are installed on the client side, reverse proxies are installed on the web server side of the network. A reverse proxy first receives requests from an unspecified number of clients and then distributes them to multiple web servers behind it.
This prevents access from concentrating on a specific server (load balancing) and helps protect web servers from external attacks.

A technology similar to proxy servers is VPNs (Virtual Private Networks). While both relay communications, they differ significantly in purpose and mechanism.

Proxy servers are mainly intended to handle specific types of traffic (such as HTTP/HTTPS) on the user’s behalf. VPNs, on the other hand, encrypt the entire communication path and create a virtual private line (tunnel), allowing all types of traffic to be sent and received securely. They are commonly used for secure connections from home to corporate networks in remote work scenarios.

The biggest difference between VPNs and proxy servers is encryption of communication. VPNs encrypt the entire communication path, providing very high security that prevents third parties from eavesdropping on or tampering with data. Proxy servers, by contrast, do not necessarily encrypt communications; their main role is to relay traffic (with some exceptions, such as HTTPS-capable proxies). Therefore, if you are handling highly confidential information, using a VPN is recommended.

By relaying Internet communications, proxy servers offer many benefits, including increased anonymity, strengthened security, and faster web display. By correctly understanding how they work, the different types, and how they differ from VPNs, you can build an optimal network environment suited to your organization’s goals and circumstances.
We hope the knowledge you gained from this article helps you enjoy a safer and more comfortable Internet experience.