Prestige 334 User’s Guide

15.13.1 Security Parameter Index (SPI)

An SPI is used to distinguish different SAs terminating at the same destination and using the same IPSec protocol. This data allows for the multiplexing of SAs to a single gateway. The SPI (Security Parameter Index) along with a destination IP address uniquely identify a particular Security Association (SA). The SPI is transmitted from the remote VPN gateway to the local VPN gateway. The local VPN gateway then uses the network, encryption and key values that the administrator associated with the SPI to establish the tunnel.

Note: Current ZyXEL implementation assumes identical outgoing and incoming SPIs

15.14 Configuring Manual Key

You only configure VPN Manual Key when you select Manual in the IPSec Keying Mode field on the Rule Setup IKE screen. This is the Rule Setup Manual screen as shown next.

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Chapter 15 VPN Screens