ZyXEL Communications Vantage CNM 2.3 User Manual page 159

Table 54 Device Operation > Device Configuration > Security > VPN > VPN Rules
(Manual) > Add/Edit (continued)
LABEL
Active Protocol
Encryption Algorithm
Authentication Algorithm
Encryption Key
Authentication Key
Apply
Cancel
Vantage CNM User's Guide
DESCRIPTION
Select ESP if you want to use ESP (Encapsulation Security
Payload). The ESP protocol (RFC 2406) provides encryption
as well as some of the services offered by AH. If you select
ESP here, you must select options from the Encryption
Algorithm and Authentication Algorithm fields.
Select AH if you want to use AH (Authentication Header
Protocol). The AH protocol (RFC 2402) was designed for
integrity, authentication, sequence integrity (replay
resistance), and non-repudiation but not for confidentiality,
for which the ESP was designed. If you select AH here, you
must select options from the Authentication Algorithm
field.
Select DES, 3DES or NULL from the drop-down list box.
When you use DES or 3DES, both sender and receiver must
know the Encryption Key, which can be used to encrypt and
decrypt the messages. 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. Select NULL to set up a
tunnel without encryption. When you select NULL, you do not
enter an encryption key.
When you use SHA1 or MD5, both sender and receiver must
know the Authentication Key, which can be used to
generate and verify a message authentication code. 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.
This field only applies when you select ESP. With DES, type a
unique key 8 ASCII characters long. With 3DES, type a
unique key 24 ASCII characters long. Any characters may be
used, including spaces, but trailing spaces are truncated.
Type a unique authentication key to be used by IPSec if
applicable. Enter 16 characters for MD5 authentication or 20
characters for SHA-1 authentication. Any characters may be
used, including spaces, but trailing spaces are truncated.
Click this to save your changes back to the device.
Click this to begin configuring this screen afresh.
Chapter 6 Device Security Settings
159