P-661H/HW Series User’s Guide

Table 84 Edit VPN Policies

LABEL

DESCRIPTION

 

 

Encryption

Select DES, 3DES, AES or NULL from the drop-down list box.

Algorithm

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.

 

Select NULL to set up a tunnel without encryption. When you select NULL, you

 

do not enter an encryption key.

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 SHA1 for maximum security.

Advanced

Click Advanced to configure more detailed settings of your IKE key management.

 

 

Apply

Click Apply to save your changes back to the ZyXEL Device.

 

 

Cancel

Click Cancel to begin configuring this screen afresh.

 

 

13.12 IKE Phases

There are two phases to every IKE (Internet Key Exchange) negotiation – phase 1 (Authentication) and phase 2 (Key Exchange). A phase 1 exchange establishes an IKE SA and the second one uses that SA to negotiate SAs for IPSec.

Figure 125 Two Phases to Set Up the IPSec SA

In phase 1 you must:

•Choose a negotiation mode.

•Authenticate the connection by entering a pre-shared key.

•Choose an encryption algorithm.

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Chapter 13 VPN Screens