ZyXEL P-2602HW-D3A User Guide - Page 239

Manual Key Setup, Configuring Manual Key

Page 239 highlights

P-2602H(W)(L)-DxA Series User's Guide Table 88 Advanced VPN Policies LABEL DESCRIPTION Authentication Select SHA1 or MD5 from the drop-down list box. MD5 (Message Digest 5) and Algorithm 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 Define the length of time before an IKE SA automatically renegotiates in this field. (Seconds) 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 Perfect Forward Secrecy (PFS) is disabled (NONE) by default in phase 2 IPSec Secrecy (PFS) 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). Back Click Back to return to the previous screen. Apply Click Apply to save your changes back to the ZyXEL Device and return to the VPN-IKE screen. Cancel Click Cancel to return to the VPN-IKE screen without saving your changes. 17.14 Manual Key Setup Manual key management is useful if you have problems with IKE key management. 17.14.1 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. Current ZyXEL implementation assumes identical outgoing and incoming SPIs. 17.15 Configuring Manual Key You only configure VPN Manual Key when you select Manual in the IPSec Key Mode field on the VPN IKE screen. This is the VPN Manual Key screen as shown next. Chapter 17 VPN Screens 239

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P-2602H(W)(L)-DxA Series User’s Guide
Chapter 17 VPN Screens
239
17.14
Manual Key Setup
Manual key management is useful if you have problems with
IKE
key management.
17.14.1
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.
Current ZyXEL implementation assumes identical outgoing and incoming SPIs.
17.15
Configuring Manual Key
You only configure
VPN Manual Key
when you select
Manual
in the
IPSec Key Mode
field
on the
VPN IKE
screen. This is the
VPN Manual Key
screen as shown next.
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).
Back
Click
Back
to return to the previous screen.
Apply
Click
Apply
to save your changes back to the ZyXEL Device and return to the
VPN-IKE
screen.
Cancel
Click
Cancel
to return to the
VPN-IKE
screen without saving your changes.
Table 88
Advanced VPN Policies
LABEL
DESCRIPTION