What is a proxy?

The main task of a proxy server is to accept, as a proxy, client requests on the server and transmit them with the corresponding IP address to the destination computer. In this type of communication there is no direct connection between the sender and the recipient. Sometimes neither the requested system nor the target computer knows that a proxy server is involved. Proxy servers can work in two ways. On the one hand, a forward proxy serves to protect the client network from influence from the Internet. If the target system, such as a web server, is protected by a rotating proxy, it can be called a reverse proxy.

Forward Proxy (Client Protection): If a proxy server is installed as the interface between the private network (LAN) and the Internet, local terminals can be effectively protected from the influence of the public network. The proxy accepts requests from the local network and transmits them with its IP address as the sender to the recipient's computer. Reply packets from the network will not be forwarded to the client on the local network, but will pass through a proxy server before reaching the final destination. In general, the trustee acts as a supervisory authority. Appropriate security systems do not need to be installed on every client on the network, but a significant number are running on proxy servers.
Reverse Proxy (Server Security): Web servers can also be secured by intercalating a proxy when accessed from a public network. Internet clients cannot directly access the target computer, but instead the proxy receives requests, checks their security settings, and forwards them securely to the server.

Scope of application of a proxy server

The implementation of proxy servers involves several factors. As a bridge between two communication partners, this network component allows data to be exchanged between two systems in situations where a direct connection cannot be established due to incompatible IP addresses, for example because one component uses IPv4 and the other uses IPv6. IPvXNUMX. Data that does not go through the direct path but is redirected to a proxy server can be filtered, buffered, and distributed across multiple target systems using load balancing. Additionally, a proxy is a key component of a firewall that protects computer systems from attacks from the public network.

• caching: This is another basic function of a proxy. In order to be able to quickly respond to constant requests from the local network, a properly configured proxy server temporarily stores a copy of the data received by the server from the Internet in a cache. The most frequently requested web content does not need to be reloaded each time it is accessed and is delivered directly, saving time and bandwidth.
• Filtration: When a proxy is installed as an interface between two computer systems, it can be used as a data transmission filter to block certain web content for clients or automatically reject anomalous requests.
• Bandwidth control and load balancing: If a proxy is used for bandwidth control, it will allocate the resources defined for network clients according to the load power. This ensures that applications don't completely block your bandwidth. Due to its role as a central interface, a proxy server allows resource-intensive client requests or server responses to be placed on different systems to evenly distribute the load within the same computer network.
• Anonymization: Since the proxy server prevents direct connection between the sender and the recipient, the client's IP address may be hidden behind the communication interface. This allows for some anonymity, since the user can operate with an external IP address and proxy location. Countries with strict censorship on Internet use or limited access to copyrighted content sometimes use a proxy server abroad to avoid geo-blocking.

Types of proxy servers

In addition to the more general definition of a proxy, there are different names for different types of proxy servers, both in terms of the technical implementation of the network components and the differences in their application. Most often, application proxy servers and scheme proxy servers, as well as dedicated and shared proxy servers, are distinguished; you can use this service at this address: https://proxy-seller.io/ 

Application and circuit proxies

Technically, some proxy servers are implemented in such a way that they can parse the data packets they are supposed to forward. In contrast, other types of proxy implementations do not allow access to data packets. However, filtering functions can be carried out, in this case, based on IP addresses sender and the specified port.  

Application Proxy: Application Proxy is based on the application layer (layer 7) of the OSI (Open System Interconnection) reference model. This type of proxy, also known as an application filter, has the functionality of analyzing data packets and blocking, modifying or forwarding them according to specified rules.
Proxy chain: The circuit proxy operates at the transport layer (layer 4) of the OSI reference model and does not have any function to analyze data packets. This type of proxy is usually used as a filtering module firewall and allows you to filter data packets by ports and IP addresses. Unlike an application proxy, a schema proxy cannot influence communication in any way. Instead, filtering is based on an all-or-nothing principle, and data packets are either allowed through or blocked.

Dedicated and shared proxies

The classification of the terms "dedicated" and "shared" depends on whether the proxy is suitable for only one communication protocol (dedicated proxy) or whether the network interface acts as a contact element for all communication protocols (general proxy).

Dedicated proxy: As the name suggests, a dedicated proxy server is configured for a specific communication protocol. For this reason, different dedicated proxy servers usually run in parallel for different protocols, such as HTTP, FTP or SMTP.  
Shared proxy server: Unlike specialized proxies, a general proxy is not a specialized server and therefore is not used for more than one communication protocol.
In practice, application proxies act as dedicated servers, while shared proxies are used as chain proxies, so the terms are often used interchangeably.