1. Definition of proxy server
Proxy Server, also known as proxy IP, is an important security function. Its work mainly in the dialogue layer of the open system interconnection (OSI) model, thus playing the role of a firewall. It is a transit station for network information and an intermediary between individual networks and Internet service providers. It is responsible for forwarding legal network information and controlling and registering forwarding. Most of them are used to connect INTERNET (International Internet) and INTRANET (local area network)
Under normal circumstances, when we use a web browser to directly connect to other Internet sites to obtain network information, we directly contact the destination site server, and then the destination site server transmits the information back. A proxy server is another server between the client and Web server . With it, the browser does not directly go to the web server to retrieve the web page, but sends a request to the proxy server. The signal will be sent to the proxy server first, and the proxy server will retrieve the information needed by the browser and transmit it to your browser.
In the URL box, enter the website address you want to visit, click on the proxy browsing and will open a new window to link the proxy server, and wait for a few seconds. If an error such as not being able to link the server at this time, please try to select another server above, because the proxy server consumes a lot of resources and is time-consuming, so it is sometimes impossible to open, and you must try the proxy server multiple times. Automatically update the latest available servers every day.
Most proxy servers have buffering functions, just like a large Cache. It has a large storage space. It constantly stores newly acquired data on its local memory. If the data requested by the browser already exists in its local memory and is latest, then it will not re-get data from the web server, but will directly transfer the data on the memory to the user's browser, which can significantly improve browsing speed and efficiency.
More importantly: the proxy server is an important security function provided by the Internet link-level gateway (Gateway). Its work mainly in the dialogue layer of the open system interconnection (OSI) model, thus playing the role of a firewall.
For the above reasons, most proxy servers are used to connect INTERNET (International Internet) and INTRANET (local area network). In China, the so-called China Multimedia Public Information Network and Education Network are both independent large national-level local area networks, isolated from the international Internet. For various needs, some groups or individuals have set up proxy servers between the two networks. If we know the address of these proxy servers, we can use it to foreign websites.
2. Function of proxy server
1. Set user verification and recording functions
2. Break through its own IP access restrictions and access foreign sites.
3. Grade management of users
4. Internet users can access foreign websites through agents.
5, improve access speed
6, access some internal resources of some units or groups, such as FTP, a university (provided that the proxy address is within the allowable access scope of the resource), using the free proxy server in the address segment of the Education Network, it can be used for various FTP download and uploading open to the Education Network, as well as various information query and sharing services.
7. Connecting the intranet and the Internet as a firewall
8. Breakthrough of China Telecom 's blockade: China Telecom users have many websites that are restricted from access. This restriction is artificial, and different servers block the address. So if you cannot access it, you can try changing to a foreign proxy server.
9. Save IP resources
10. Improve access speed: Usually, the proxy server sets a larger hard disk buffer. When external information passes, it is also saved in the buffer. When other users access the same information, the information is directly retrieved from the buffer and passed to the user to improve access speed.
11. Protect the regionality of resources
12. Hide the real IP: Internet users can also hide their IP in this way to avoid attacks.
3. Classification of proxy server
http proxy refers to the behavior of transferring data accessed using http (http data stream) to a third party (such as website-agent-your computer); or a server with the function of forwarding http messages. www is very familiar to everyone who surfs the Internet. www connection request is the http protocol, so when we browse the web page and download data (the ftp protocol can also be used). It is usually bound to ports 80, 3128, 8080 and other ports of the proxy server.
2, HTTPS proxy:
https proxy is a type of web proxy and is the most widely used very simple communication protocol when transmitting information on the Internet. HTTPS (Secure Hypertext Transfer Protocol) Secure Hypertext Transfer Protocol, it is developed by Netscape and built into its browser to compress and decompress data and return the results sent back on the network. HTTPS actually applies Netscape's full socket layer (SSL) as a sublayer of the HTTP application layer. (HTTPS uses port 443 instead of using port 80 to communicate with TCP/IP like HTTP.) SSL uses 40-bit keywords as the RC4 stream encryption algorithm, which is suitable for encryption of commercial information. HTTPS and SSL support X.509 digital authentication, and users can confirm who the sender is if needed.
3, SOCKS proxy
Socks proxy is a proxy based on the Socks protocol, also called an all-round proxy. SOCKS proxy is different from other types of proxy. It simply passes data packets without caring about what kind of application protocol it is. It can be an HTTP request, so the SOCKS proxy server is much faster than other types of proxy servers. A proxy server using the socks protocol is a SOCKS server, which is a general proxy server. Socks is a circuit-level underlying gateway, developed by David Koblas in 1990 and has been an open standard for Internet RFC standards since then. Socks does not require applications to follow a specific operating system platform. Socks proxy is different from application-layer proxy and HTTP-layer proxy. Socks proxy simply passes packets without having to care about what application protocol (such as FTP, HTTP and NNTP requests). So, Socks proxy is much faster than other application-level proxy. It is usually bound to port 1080 of the proxy server. If you are on the enterprise or campus network, you may need to use SOCKS to access the Internet through a firewall or through a proxy server. Generally, it is not necessary for dial-up users to use it. Note that the proxy server commonly used when browsing web pages is usually a dedicated http proxy, which is different from SOCKS. Therefore, your ability to browse the web does not mean that you can definitely access the Internet through SOCKS. Commonly used firewalls or proxy software support SOCKS, but its administrator requires this function to be turned on. If you are not sure if you need SOCKS or if there is SOCKS available, please contact your network administrator.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-