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Prestige 652 Series User’s Guide
17-18
VPN
Screens
Table 17-8 VPN IKE: Advanced
LABEL
DESCRIPTION
Authentication
Algorithm
Select
SHA1
or
MD5
from the drop-down list box. MD5 (Message Digest 5) and
SHA1 (Secure Hash Algorithm) are hash algorithms used to authenticate packet
data. The SHA1 algorithm is generally considered stronger than MD5, but is
slower. Select
MD5
for minimal security and
SHA-1
for maximum security.
SA Life Time
(Seconds)
Define the length of time before an IKE SA automatically renegotiates in this field.
It may range from 60 to 3,000,000 seconds (almost 35 days).
A short SA Life Time increases security by forcing the two VPN gateways to
update the encryption and authentication keys. However, every time the VPN
tunnel renegotiates, all users accessing remote resources are temporarily
disconnected.
Encapsulation Select
Tunnel
mode or
Transport
mode from the drop-down list box.
Perfect Forward
Secrecy (PFS)
Perfect Forward Secrecy (PFS) is disabled (
NONE
) by default in phase 2 IPSec
SA setup. This allows faster IPSec setup, but is not so secure. Choose
DH1
or
DH2
from the drop-down list box to enable PFS.
DH1
refers to Diffie-Hellman
Group 1 a 768 bit random number.
DH2
refers to Diffie-Hellman Group 2 a 1024
bit (1Kb) random number (more secure, yet slower).
Apply
Click
Apply
to save your changes back to the Prestige and return to the
VPN IKE
screen.
Cancel
Click
Cancel
to return to the
VPN IKE
screen without saving your changes.
17.12 Manual Key Setup
Manual key management is useful if you have problems with
IKE
key management.
17.12.1
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.
Summary of Contents for Prestige 652
Page 1: ...Prestige 652 Series ADSL Security Wireless LAN Router User s Guide Version 3 40 August 2003...
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Page 104: ...Prestige 652 Series User s Guide 7 12 WAN Setup Figure 7 6 Advanced WAN Backup...
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Page 192: ...Prestige 652 Series User s Guide 17 8 VPN Screens Figure 17 3 VPN IKE...
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Page 252: ...Maintenance VIII Part VIII Maintenance This part covers the maintenance screens...
Page 254: ...Prestige 652 Series User s Guide 22 2 Maintenance Figure 22 1 System Status...
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