Introduction to secure router networking and IPSec technology

A large enterprise/company needs to be distributed across the country branches or offices across the wide area network, so as to share information resources between each other, because the need to transfer data on the public data network, it is known that the public data on the Internet transmission of data information is not particularly safe. To improve the security of the data being transmitted, consider using a secure router. A secure router can hide the network topology diagram within the company, at the same time can also encrypt the data needs to be transmitted, so that even if the data transmitted to other users on the public network to intercept, they can not through the IP packet to obtain the company's internal network IP address and to understand the internal network topology map, encrypted data, There is no specific decryption tool The general user is not likely to know the contents of the packet transmitted. The network topology diagram using the secure router is shown in the following illustration:

Graph using Secure router networking

Because the security router has the function of data encryption, the data need to transmit on the LAN is sent out through the secure router, the secure router will encrypt the data according to certain encryption algorithm, and receive the data to restore the data by using the same algorithm.

The tunneling mode of IPSec for secure routers also has the ability to hide the internal network topology map. A secure router encapsulates all IP packets that need to be sent, encapsulating the IP address of the source and destination gateways on the original IP packet, and the destination router docking the IP packets received, removing the increased IP header of IPSec , and then sends the IP packet to the destination host on the LAN based on the IP packet's source and destination address.

When a user on Lan a wants to send data to a user on LAN B, first, a user's IP message through the export of secure routers is repackaged, in the original IP packet packaging source and destination gateway IP address, packaged IP packets to the destination B-side of the secure router, can be automatically identified, At the same time, IP packets are decompressed and eventually transferred to B-end users.