Prestige 334 User’s Guide
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Chapter 15 VPN Screens
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.
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.
Note:
Current ZyXEL implementation assumes identical
outgoing and incoming SPIs