Basic knowledge about proxy servers

Internet users are no longer familiar with the Internet, and now they are already working-class families. More and more companies have connected their internal networks to the Internet. Of course, there are many ways to connect to the Internet. For ordinary people, it is to buy a MODEM to connect to the Internet using PSTN (public service telephone network. However, some companies generally use DDN or ISDN access and rent a month. Of course, an individual cannot afford the monthly rental fee. How can I use a telephone line to enable Internet access for many people? This involves the Proxy Server and how to use the Proxy Server.

What is Proxy? It is a Proxy. Common Internet access is a typical client and server structure: users use client programs on computers to send requests to browsers, and remote WWW server programs respond to requests and provide corresponding data. The Proxy is between the client and the server. For the server, the Proxy is the client, the Proxy initiates a request, and the server responds. for the client, the Proxy is the server and it accepts the client's request, and transfer the data uploaded by the server to the client. It acts like a real-life proxy service provider. Therefore, the Chinese name of the Proxy Server is the Proxy Server.

The working principle of the Proxy Server is: after the client sets the Proxy Server in the browser, the requests that you access all WWW sites using the browser will not be sent directly to the target host, but will be sent to the Proxy Server first, after the Proxy Server accepts the customer's request, the proxy server sends a request to the target host and accepts the data of the target host, which is stored in the hard disk of the proxy server, then, the proxy server sends the data requested by the customer to the customer.
The proxy server has four functions:

1. Improve access speed. Because the data requested by the customer is stored in the hard disk of the proxy server, the next time this customer or another customer requests data of the same destination site, the data will be directly read from the hard disk of the proxy server, the proxy server plays a role in caching. When many customers access popular websites, the proxy server has more obvious advantages.

2. Proxy can act as a firewall. Because all users who use the proxy server must access the remote site through the proxy server, you can set restrictions on the proxy server to filter or shield some information. This is the most common method for lan network management to limit the access scope of LAN users, and also the reason why LAN users cannot browse some websites. If a dial-up user uses a proxy server, the user must also be subject to the access restrictions of the proxy server, unless you do not use this proxy server.

3. Access websites that cannot be accessed directly through the proxy server. There are many open proxy servers on the Internet. When the user's access permissions are restricted, the access permissions of these proxy servers are unrestricted, just as the proxy server is within the access range of the customer, therefore, it is possible for the customer to access the target website through the proxy server. Colleges and Universities in China mostly use the education network and cannot go abroad. However, they can access the Internet through proxy servers, which is why proxy servers in colleges and universities are hot.

4. Improved security. Whether you are visiting a chat room or website, the target website can only know that you are from the proxy server, and your real IP address cannot be tested, which improves the security of users.
Proxy Server Settings:

To set the proxy server, you must first know the proxy server address and port number, and then enter the corresponding address and port number in the proxy server settings column of IE or NC. Assume that the address of a proxy server is Proxy.net.net and the port number is 3000. in IE, the configuration method is to use the Internet option/connection/Proxy server in the View menu, then, hook up in the check box before accessing the Internet through the proxy server and enter the proxy server address in the address box. In this example, assume that the proxy server address is proxy.net.net, fill in port 3000 in the port box, click the application button at the bottom, and click OK. The setting is complete. When you use IE again, you will find that IE is always connected to the proxy server no matter what website you visit. If you use NC, set it to a little more complex. Use the Preferences menu item under the edit menu, and then select Proxies under Advanced. In the Proxies option on the right, select the second Manral Proxy configuration, and then click View on the right... The configuration page of the proxy server appears. Fill in the corresponding content in the proxy server address and port number column, click OK, return to the parameter settings window, and click OK, the configuration of the proxy server is complete. When the customer browses the web page again, it will automatically send an application to the proxy server you set and get the data. When browsing the website, both IE and NC can clearly see the process of connecting to the proxy server and then the target website in the browser status bar.

However, do not confuse the Proxy Server with the Router. The Proxy Server is a service software built on the application layer, while the Router is a network device or a computer, it works on the IP layer and forwards data to the IP layer. Generally, a Proxy Server works on a computer with both a MODEM and a nic. Different Proxy servers provide different services, generally WWW, FTP, and other common services. Each passenger must have an independent IP address in the intranet, configure the Proxy Server and the port number pointing to the Proxy Server IP address and service in "connection" in "Control Panel-Internet item" of the passenger plane. When the Proxy Server is started, it uses Winsock. dll to open up a specified service port and wait for the request from the passenger plane. After the Proxy Server's MODEM is dial-up, your Proxy Server will work. When you send a connection request to your IE, your passenger plane directly sends the packet to the Proxy Server. When the Server captures this IP packet, first analyze what request it is, if it is an HTTP request, the Proxy Server sends an HTTP request to your ISP. When the Proxy Server receives a response, it forwards the IP packet to the internal network, your plane will get this IP package. In addition, your Proxy Server can also be used as a good firewall. For more information, see the readme file of your Proxy Server.

When you access a Web server on the internet, how many pieces of personal information will be leaked to others? When accessing the internet, the Web browser sends at least 20 pieces of personal information about you to the Web server without your awareness. If the personal information is sent to a well-known website or a Web server of a large enterprise, there will be no major problems. It would be disturbing if it was transferred to a Web server that was not clear to anyone who opened the website. The information sent by the Web browser to the Web server is "environmental variable" in line ". The main contents are as follows: (1) ip address assigned to the computer (REMOTE_A DDR) and host name (REMOTE_HOST); (2) port number used by the Web browser (REMOTE_PORT); (3) the product name of the Web browser (HTTP_USER_AGENT); (4) the latest website address (HTTP_REFERER) among others.

Although the above items do not contain personal information such as email addresses and names, the IP addresses and host names in (1) are difficult to ensure security, but what method can I use to hide my IP address?

Solving this problem is actually very simple. You only need to access the Web server through the proxy server. The proxy server can handle access requests from various terminals for the Web server. In terms of Enterprise Networks, proxy servers are deployed on the areas of the company's internal LAN and Internet connections. You can access the Internet by using the proxy server provided by the Internet connection provider.