Destination of proxies and NAT
A proxy server is designed to mediate between a workstation and a worldwide network.
The proxy computer passes user requests through itself and then returns the results received from Inetrnet. This is a kind of “trustee”, contributing to the simultaneous access of all machines on the local network to the Internet. At the same time, the administrator setting up the grid is relieved of the need to assign an IP address to each individual point, build a complex routing scheme, and contact the provider for an additional (usually paid) service.
In addition to unnecessary troubles and unjustified high cost with methods that, fortunately, are already a thing of the past, the level of data security in LAN is lost, making each computer a potential target for virus attacks and hacker hacks. In addition, due to the lack of centralized management, the administrator will have to worry about the control of each individual station. And, by the way, with the second method of setting the LAN access to the Internet, you also need an additional program to the main computer, which will route packets, but, unlike proxies, transmitting real IP-clients of clients.
A router that knows how to change addresses is called NAT-proxy (from the English abbreviation network address translation, which can be translated as “network address translator”).
NAT is the first, simplest form of this program, such a transitional link from one type of LAN settings to another type. Under the name “Sharing access to a boarding school”, NAT-proxy is already found in Windows 2000 and XP. This program is designed for the average user who is not required to possess in-depth knowledge of a qualified system administrator. For work it is not required to carry out any specialized tricky settings. But, in fact, this advantage is very doubtful. NAT, being a universal proxy, is not able to penetrate the intricacies of application protocols. Therefore, for a more correct and safe operation, it is worth familiarizing yourself with specialized proxy programs.
The most common software in its class is HTTP-proxy. From the name it becomes clear that the principle of organizing work according to the HTTP protocol is laid down. No serious network can do without this program. What can she do:
Save files received from the Internet to a server disk, which allows you to retrieve existing data without requesting a WWW upon a second request, increasing speed and saving overall traffic.
Restrict access to resources. For example, do not let clients on sites from the “black list”. Or not all customers, but only a certain group. Or not for the entire time you are online, but only at certain hours. This advantage opens up the widest possibilities for organizing the client part of the local network.
Manage download priorities. This helps to avoid the complete absorption of traffic by lovers of free music or watching online movies.
Count the traffic used in a given time period.
Rate various resources
And even this rather extensive list of HTTP-proxy skills is not a complete listing of its advantages. HTTP-proxy is also capable of working with FTP servers. But with the mutual conversion of FTP and HTTP, the nuances of FTP functionality are partially lost. Naturally, for the specialized ftp-clients to work correctly, specialized software is also preferable. FTP proxy can be an integral part of HTTP proxy or a separate program, as in Eserv and Eproxy. To emphasize this point, proxies from Eserv and Eproxy are commonly referred to as FTP-gate.
Separate is the part selected from HTTP for working with classified information – the NTTPS proxy. The mapping proxy aims to configure through proxies the work of those programs that are used to accessing Internet resources without any mediation, for example, email services like The Bat and Outlook Express. For these purposes, a local image of the server requested by the program is installed. That is, this is a kind of deception, a trick, which, however, almost always works.
Socks-proxy – a program that is gaining momentum in popularity by providing customers with the ability to transparently use services behind firewalls. Our proxy lists contain a selection of working socks proxies. Eserv and Eproxy implement all of the listed (except NAT) types of proxies.