ZyXEL SBG3300-NB00 User Guide - Page 278

Chapter 20 IPSec VPN 20.3 What You Need To Know A VPN tunnel is usually established in two phases. Each phase establishes a security association (SA), a contract indicating what security parameters the Device and the remote IPSec router will use. The first phase establishes an Internet Key Exchange (IKE) SA between the Device and remote IPSec router. The second phase uses the IKE SA to securely establish an IPSec SA through which the Device and remote IPSec router can send data between computers on the local network and remote network. The following figure illustrates this. Figure 116 VPN: IKE SA and IPSec SA NetNwEToWrOkRAK Network B IPSec SA X Y IKE SA In this example, a computer in network A is exchanging data with a computer in network B. Inside networks A and B, the data is transmitted the same way data is normally transmitted in the networks. Between routers X and Y, the data is protected by tunneling, encryption, authentication, and other security features of the IPSec SA. The IPSec SA is established securely using the IKE SA that routers X and Y established first. 20.4 The Setup Screen The following figure helps explain the main fields in the web configurator. Figure 117 IPSec Fields Summary Local Network Remote Network Remote IPSec Router Local IP Address VPN Tunnel Local and remote IP addresses must be static. Remote IP Address 278 SBG3300-N Series User's Guide