ZyXEL Communications ZyWALL 5 User Manual page 202

ZyWALL 5 Internet Security Appliance
LABEL
My IP Address Enter the WAN IP address of your ZyWALL. The VPN tunnel has to be rebuilt if this IP
address changes.
The following applies if this field is configured as 0.0.0.0:
The ZyWALL uses the current ZyWALL WAN IP address (static or dynamic) to set up the
VPN tunnel.
If the WAN connection goes down, the ZyWALL uses the dial backup IP address for the
VPN tunnel when using dial backup or the LAN IP address when using traffic redirect.
See the chapter on WAN for details on dial backup and traffic redirect.
Secure Gateway Type the WAN IP address or the URL (up to 31 characters) of the IPSec router with
Addr which you're making the VPN connection.
IPSec Property
SPI Type a unique SPI (Security Parameter Index) from one to four characters long. Valid
Characters are "0, 1, 2, 3, 4, 5, 6, 7, 8, and 9".
Encapsulation Select Tunnel mode or Transport mode from the drop-down list box.
Mode
ESP 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 (described next).
Select DES, 3DES or NULL from the drop-down list box.
Encryption
Algorithm
When DES is used for data communications, both sender and receiver must know the
Encryption 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. 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 SHA1
Algorithm (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.
AH 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
(described next).
Authentication Select SHA1 or MD5 from the drop-down list box. MD5 (Message Digest 5) and SHA1
Algorithm (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.
Encryption Key With DES, type a unique key 8 characters long. With 3DES, type a unique key 24
(Only with ESP) characters long. Any characters may be used, including spaces, but trailing spaces are
truncated.
Authentication Key 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.
Apply Click Apply to save your changes back to the ZyWALL.
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Table 13-9 VPN Manual Setup
DESCRIPTION
VPN Screens