Prestige 662H/HW Series User’s Guide

Table 72 VPN IKE (continued)

LABEL

DESCRIPTION

 

 

Pre-Shared Key

Type your pre-shared key in this field. A pre-shared key identifies a

 

communicating party during a phase 1 IKE negotiation. It is called "pre-shared"

 

because you have to share it with another party before you can communicate with

 

them over a secure connection.

 

Type from 8 to 31 case-sensitive ASCII characters or from 16 to 62 hexadecimal

 

("0-9", "A-F") characters. You must precede a hexadecimal key with a "0x” (zero

 

x), which is not counted as part of the 16 to 62 character range for the key. For

 

example, in "0x0123456789ABCDEF", “0x” denotes that the key is hexadecimal

 

and “0123456789ABCDEF” is the key itself.

 

Both ends of the VPN tunnel must use the same pre-shared key. You will receive a

 

“PYLD_MALFORMED” (payload malformed) packet if the same pre-shared key is

 

not used on both ends.

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 SHA-1for maximum security.

Advanced

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

 

 

Back

Click Back to return to the previous screen.

 

 

Apply

Click Apply to save your changes back to the Prestige.

 

 

Cancel

Click Cancel to begin configuring this screen afresh.

 

 

Delete

Click Delete to delete the current rule.

 

 

19.11 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.

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Chapter 19 VPN Screens