Chapter 14 IPSec VPN

 

Table 67 SECURITY > VPN > VPN Rules (IKE) > Edit Gateway Policy (continued)

 

LABEL

DESCRIPTION

 

 

Server Mode

Select Server Mode to have this ZyWALL authenticate extended authentication

 

 

 

clients that request this VPN connection.

 

 

 

You must also configure the extended authentication clients’ usernames and

 

 

 

passwords in the authentication server’s local user database or a RADIUS server

 

 

 

(see Chapter 16 on page 323).

 

 

 

Click Local User to go to the Local User Database screen where you can view

 

 

 

and/or edit the list of user names and passwords. Click RADIUS to go to the

 

 

 

RADIUS screen where you can configure the ZyWALL to check an external

 

 

 

RADIUS server.

 

 

 

During authentication, if the ZyWALL (in server mode) does not find the extended

 

 

 

authentication clients’ user name in its internal user database and an external

 

 

 

RADIUS server has been enabled, it attempts to authenticate the client through

 

 

 

the RADIUS server.

 

 

 

 

 

 

Client Mode

Select Client Mode to have your ZyWALL use a username and password when

 

 

 

initiating this VPN connection to the extended authentication server ZyWALL.

 

 

 

Only a VPN extended authentication client can initiate this VPN connection.

 

 

 

 

 

 

User Name

Enter a user name for your ZyWALL to be authenticated by the VPN peer (in

 

 

 

server mode). The user name can be up to 31 case-sensitive ASCII characters,

 

 

 

but spaces are not allowed. You must enter a user name and password when you

 

 

 

select client mode.

 

 

 

 

 

 

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

Select which key size and encryption algorithm to use in the IKE SA. Choices are:

 

 

Algorithm

DES - a 56-bit key with the DES encryption algorithm

 

 

 

3DES - a 168-bit key with the DES encryption algorithm

 

 

 

AES - a 128-bit key with the AES encryption algorithm

 

 

 

The ZyWALL and the remote IPSec router must use the same algorithms and

 

 

 

keys. Longer keys require more processing power, resulting in increased latency

 

 

 

and decreased throughput.

 

 

 

 

 

 

Authentication

Select which hash algorithm to use to authenticate packet data in the IKE SA.

 

 

Algorithm

Choices are SHA1 and MD5. SHA1 is generally considered stronger than MD5,

 

 

 

but it is also slower.

 

 

 

 

 

 

SA Life Time

Define the length of time before an IKE SA automatically renegotiates in this field.

 

 

(Seconds)

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

Select which Diffie-Hellman key group (DHx) you want to use for encryption keys.

 

 

 

Choices are:

 

 

 

DH1 - use a 768-bit random number

 

 

 

DH2 - use a 1024-bit random number

 

 

 

 

 

 

Enable Multiple

Select this to allow the ZyWALL to use any of its phase 1 key groups and

 

 

Proposals

encryption and authentication algorithms when negotiating an IKE SA.

 

 

 

When you enable multiple proposals, the ZyWALL allows the remote IPSec

 

 

 

router to select which phase 1 key groups and encryption and authentication

 

 

 

algorithms to use for the IKE SA, even if they are less secure than the ones you

 

 

 

configure for the VPN rule.

 

 

 

Clear this to have the ZyWALL use only the configured phase 1 key groups and

 

 

 

encryption and authentication algorithms when negotiating an IKE SA.

 

 

 

 

 

 

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ZyWALL 2 Plus User’s Guide