ZyXEL Communications vantage cnm ユーザーズマニュアル

Chapter 6 Device Security Settings

Vantage CNM User’s Guide

In the VPN Rule (IKE) screen, click the Add icon from a gateway policy or click Edit from 
an existing network policy to display the Network Policy screen.

Password

Enter the corresponding password for the above user name. The password 
can be up to 31 case-sensitive ASCII characters, but spaces are not allowed.

IKE Proposal

Negotiation Mode

Select Main or Aggressive from the drop-down list box. Multiple SAs 
connecting through a secure gateway must have the same negotiation mode.

Encryption Algorithm

Select DES, 3DES or AES from the drop-down list box. 
When you use one of these encryption algorithms for data communications, 
both the sending device and the receiving device must use the same secret 
key, which can be used to encrypt and decrypt the message or to generate 
and verify a message authentication code. The DES encryption algorithm 
uses a 56-bit key. Triple DES (3DES) is a variation on DES that uses a 168-bit 
key. As a result, 3DES is more secure than DES. It also requires more 
processing power, resulting in increased latency and decreased throughput. 
This implementation of AES uses a 128-bit key. AES is faster than 3DES.

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 180 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. 

Key Group

You must choose a key group for phase 1 IKE setup. DH1 (default) refers to 
Diffie-Hellman Group 1 a 768 bit random number. DH2 refers to Diffie-
Hellman Group 2 a 1024 bit (1Kb) random number. 

Enable Multiple 
Proposals

Select this check box to allow the device to use any of its phase 1 or phase 2 
encryption and authentication algorithms when negotiating an IPSec SA. 
When you enable multiple proposals, the device allows the remote IPSec 
router to select which encryption and authentication algorithms to use for the 
VPN tunnel, even if they are less secure than the ones you configure for the 
VPN rule.
Clear this check box to have the device use only the phase 1 or phase 2 
encryption and authentication algorithms configured below when negotiating 
an IPSec SA.

Apply

Click Apply to save your changes back to the device.

Cancel

Click Cancel to exit this screen without saving.

Table 48   Device Operation > Device Configuration > Security > VPN > VPN Rules (IKE) > 

Gateway Policy Add/Edit