Proxy Server refers to proxy software or proxy server, and can also be considered as a network access method. It is an important server security function, and its work is mainly in the session layer of the Open Systems Interconnection (OSI) model, thus acting as a firewall.
As a bridge connecting the Internet and the Intranet, the proxy server plays an extremely important role in practical applications.
The most basic function of a proxy server is to connect, and it is mostly used to connect to the Internet (international Internet) and Local Area Network (local area network). It also includes functions such as security, caching, content filtering, and access control management.
The function of Proxy Server: make a backup copy of the files and web page data accessed by the remote before in the proxy at the local end. Check to see if anyone else has been on the same website before, and if so, you can send back data directly without connecting to the outside world.
The role of proxy server
Improve internal access speed
Can act like a firewall
Visit some websites that cannot be accessed directly
Internet access security is improved
related access restrictions
Traffic throttling that affects bandwidth too much
Block some access requests that affect the company’s internal traffic
Port setting restrictions to prevent illegal attacks
Why open a proxy server
Connect to the Internet (firewall): Because all intranet users access the outside world through the proxy server, they are only mapped to one IP address, so the outside world cannot directly access the internal network;
At the same time, IP address filtering can be set to limit the access rights of the intranet to the outside world; in addition, two intranets that are not interconnected can also be interconnected through a third-party proxy server to exchange information.
Save IP overhead: As mentioned above, all users only occupy one IP externally, so there is no need to rent too many IP addresses, which reduces the maintenance cost of the network.
In this way, many machines in the local area network that are not connected to the external network can be connected to the external network through a proxy server of the internal network, which greatly reduces the cost. Of course, it also has its downside. For example, many network hackers hide their real IP addresses through this method and escape surveillance.
Improve access speed: The bandwidth itself is small, and the target host is connected through a proxy with a large bandwidth. And usually the proxy server sets a large hard disk buffer (maybe up to several GB or more), when there is information from the outside world, it also saves it in the buffer, when other users access the same information When it is, the information is directly taken out from the buffer and passed to the user, so as to achieve the purpose of improving the access speed.