VPN-Virtual Private Network

VPN, fully called Virtual Private Network, is translated as a wireless virtual private network, which is mainly used to establish a private network on the public network for encrypted communication. Such a statement may be somewhat abstract. Let's take an example. Assume that the ERP system server built in the A network of a company's headquarters is 192.168.1.251. The computer at the headquarters can access it directly through the intranet address, but the branch B in the field cannot. When accessing the intranet address, the VPN plays a very important role. Branch B can access the server through the built-in virtual private network to access the LAN of the headquarters A.

How VPN works?

1. The VPN gateway generally adopts a dual network card structure. The internal network card accesses the internal local area network of the company headquarters A, and the external network card uses the public IP to access the Internet. Assume that the terminal 192.168.2.2 of branch B needs to access the server 192.168.1.252 of the headquarters A, and the destination address of the access packet sent by it is 192.168.1.252.
2. The VPN gateway of the branch office LAN B checks the target address 192.168.1.252 when it receives the access packet 1 sent by the terminal 192.168.2.2, and finds that the destination address belongs to the address of the headquarters A network, so the packet 1 is based on the The VPN technology is used for encapsulation, and the VPN gateway constructs a new VPN packet 2, and the encapsulated original packet 1 is used as the load of the VPN packet 2. The destination address of the VPN packet is the VPN of the company headquarters A network. The public IP address of the gateway.
3. The VPN gateway of the branch B LAN sends the VPN packet to the Internet external network. Since the destination address of the VPN packet is the external address of the VPN gateway of the headquarters A network, the packet will be correctly routed by the Internet. Send to the VPN gateway of the headquarters A network.
4. The VPN gateway of the headquarters A network checks the received data packet 2, and if it finds that the data packet is sent from the VPN gateway of the branch B network, it can determine that the data packet is a VPN data packet, and the data is The package is unpacked. The process of unpacking is mainly to strip the header of the VPN packet and restore the payload to the original packet by reverse processing.
5. The VPN gateway of the headquarters A network sends the restored original data packet to the target server 192.168.1.252. In the server 192.168.1.252, the packet it received is the same as that sent directly from the terminal 192.168.2.2.
6. The packet processing procedure from the server 192.168.1.252 to the terminal 192.168.2.2 is the same as the above process principle. This completes the entire access through the VPN.

About the Company

E-Lins is a leading provider of industrial 4g router, sim card wifi router 4g, 4G modem, dual sim 4g router and router LTE. The company prides itself on delivering the best equipment at highly competitive prices to its customers around the world.

E-Lins is a leading provider of industrial 4g router, sim card wifi router 4g, 4G modem, dual sim 4g router and router LTE. The company prides itself on delivering the best equipment at highly competitive prices to its customers around the world.