ZyXEL Communications G.SHDSL.bis 4-port Security Gateway P-793H - Manual (Page 176)

P-793H User’s Guide
176 Chapter 11 IPSec VPN
11.6 Viewing SA Monitor
Click Security, VPN and Monitor to open the SA Monitor screen as shown. Use this screen
to display and manage active VPN connections.
When there is outbound traffic but no inbound traffic, the SA times out automatically after two
minutes. A tunnel with no outbound or inbound traffic is "idle" and does not timeout until the
SA lifetime period expires. You can also configure the ZyXEL Device to renegotiate an IPSec
SA when the SA lifetime expires, even if there is no traffic.
Security Protocol
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).
Encryption
Algorithm
Select DES, 3DES or NULL from the drop-down list box.
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 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.
Encryption Key With DES, type a unique key 8 characters long. With 3DES, type a unique key 24
characters long. Any characters may be used, including spaces, but trailing
spaces are truncated.
Authentication
Algorithm
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 SHA1 for maximum security.
Authentication Key Type a unique authentication key to be used by IPSec if applicable. Enter 16
characters for MD5 authentication or 20 characters for SHA1 authentication. Any
characters may be used, including spaces, but trailing spaces are truncated.
Back Click Back to return to the previous screen.
Apply Click Apply to save your changes back to the ZyXEL Device.
Reset Click Reset to begin configuring this screen afresh.
Table 53 VPN > Setup > Edit > Manual (continued)
LABEL DESCRIPTION