ZyXEL Communications P-334W - Manual (Page 239)

Prestige 334W User’s Guide
VPN Screens 16-29
Table 16-9 Rule Setup: Manual
LABEL DESCRIPTION
Remote Port End Enter a port number in this field to define a port range. This port number must
be greater than that specified in the previous field. If Remote Port Start is left
at 0, Remote Port End will also remain at 0.
DNS Server (for IPSec
VPN)
If there is a private DNS server that services the VPN, type its IP address here.
The Prestige assigns this additional DNS server to the Prestige’s DHCP clients
that have IP addresses in this IPSec rule's range of local addresses. A DNS
server allows clients on the VPN to find other computers and servers on the
VPN by their (private) domain names.
My IP Address Enter the WAN IP address of your Prestige. The Prestige uses its current WAN
IP address (static or dynamic) in setting up the VPN tunnel if you leave this field
as 0.0.0.0. The VPN tunnel has to be rebuilt if this IP address changes.
Secure Gateway IP
Address Type the WAN IP address or the URL (up to 31 characters) of the IPSec router
with which you're making the VPN connection.
SPI Type a number (base 10) from 1 to 999999 for the Security Parameter Index.
Encapsulation Mode Select Tunnel mode or Transport mode from the drop-down list box.
Enable Replay
Detection As a VPN setup is processing intensive, the system is vulnerable to Denial of
Service (DoS) attacks The IPSec receiver can detect and reject old or duplicate
packets to protect against replay attacks. Select YES from the drop-down menu
to enable replay detection, or select NO to disable it.
IPSec Protocol 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 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 later).
Encryption Algorithm Select DES or 3DES from the drop-down list box. The Prestige's encryption
algorithm should be identical to the secure remote gateway. When DES is used
for data communications, both sender and receiver must know the same secret
key, which can be used to encrypt and decrypt the message. 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.