Tunnel forwarding is a very important technical means in crawler proxy. It has a wide range of application scenarios in practical applications by establishing encrypted communication channels, bypassing network blockades and restrictions, improving network security, accelerating network access, and protecting user privacy. This article will introduce the relevant knowledge points of tunnel forwarding in detail, including basic concepts, working principles, and usage scenarios in practical applications.
1. Basic concepts
Tunnel forwarding is a technology that establishes an encrypted communication channel between the proxy server and the client through encryption and technical means. This channel can avoid being detected and intercepted by the network supervision department, thereby protecting the security and privacy of network communication.
In tunnel forwarding, the proxy server is an intermediary station, which receives the client's request and forwards it to the target server. At the same time, the proxy server also receives the response from the target server and forwards it to the client. Tunnel forwarding can use different protocols and technologies, such as HTTP, HTTPS, SOCKS, etc.
2. Working principle
The working principle of tunnel forwarding can be summarized as the following steps:
1. The client establishes a connection with the proxy server
First, the client establishes an encrypted communication channel by establishing a connection with the proxy server. This channel can use different protocols and technologies, such as HTTP, HTTPS, SOCKS, etc.
2. The proxy server establishes a connection with the target server.
The proxy server establishes a connection with the target server and forwards the client's request to the target server. This process can use the same protocol and technology or a different protocol and technology.
3. The target server returns a response
The target server processes the client's request and returns the response to the proxy server. After the proxy server receives the response, it forwards it to the client.
4. Close the connection
When the client completes the request, close the connection with the proxy server. The proxy server also closes the connection to the target server to release resources.
3. Usage scenarios
The tunnel forwarding crawler agent has the following scenarios in practical application:
1. Through network blockade
In some countries or regions, the network supervision department will restrict or block certain websites or services. The purpose of this blocking is to prevent these websites or services from being accessed, so as to protect user privacy data and security. The tunnel forwarding crawler proxy can help users bypass these restrictions to access blocked websites or services. For example, accessing social media sites such as Facebook and Twitter is restricted in some countries or regions, and crawler agents that use tunnel forwarding can bypass these restrictions, visit these sites and obtain relevant information.
2. Improve network security
In some scenarios where sensitive information needs to be protected, tunnel forwarding crawler agents can provide higher network security by establishing encrypted communication channels to protect the security and privacy of data transmission. For example, in some financial insurance institutions, governments, etc., it is necessary to protect users' personal privacy information from being leaked, so tunnel forwarding crawler agents can be used to protect the security and privacy of data transmission.
3. Accelerate network access
In some areas or network environments, the network speed is slow or unstable, which will affect the user's network experience. Therefore, the crawler proxy using tunnel forwarding can optimize network access speed and improve network stability and response speed.
4. Anonymous network access
In some scenarios that need to protect user privacy, such as investigating human rights and rights protection, tunnel forwarding crawler agents can provide anonymous network access functions to protect users’ privacy and security by hiding users’ real IP addresses and geographic location information.
4. Classification and Implementation of Tunnel Forwarding Technology
Tunnel forwarding technologies can be classified into the following categories according to different implementation methods:
1. HTTP-based tunnel forwarding
HTTP-based tunnel forwarding is a common tunnel forwarding method. It uses the HTTP protocol as a communication protocol to establish an encrypted channel between the proxy server and the client. The specific implementation method is as follows: When the
client establishes an HTTP connection request with the proxy server, it uses the HTTP POST or GET method to transmit the data to the proxy server. The proxy server forwards the data to the target server
and forwards the response of the target server back to the client client
.
2. SOCKS5 is an implementation of HTTP-based tunnel forwarding.
It realizes the establishment of an encrypted channel between the proxy server and the client by encapsulating the HTTP protocol in the SOCKS protocol, and supports data transmission of the TCP and UDP protocols.
3. DAILI-based tunnel forwarding
DAILI-based tunnel forwarding is a technology that establishes an encrypted channel between the proxy server and the client by establishing a virtual private network DAILI. The specific implementation method is as follows:
when the client establishes a DAILI connection with the DAILI proxy server and requests data, the DAILI protocol is used for encrypted transmission to ensure data security and privacy.
The DAILI proxy server encrypts the data and forwards it to the target server, and encrypts the data of the target server
