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15 viewing sa monitor – ZyXEL Communications P-335WT User Manual

Page 237

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P-335 Series User’s Guide

Chapter 17 VPN Screens

237

17.15 Viewing SA Monitor

In the web configurator, click VPN and the SA Monitor tab. Use this screen to display and
manage active VPN connections.

A Security Association (SA) is the group of security settings related to a specific VPN tunnel.
This screen displays active VPN connections. Use Refresh to display active VPN
connections. This screen is read-only. The following table describes the labels in this tab.

Note: 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.See

the Keep Alive section

to

have the Prestige renegotiate an IPSec SA when the SA
lifetime expires, even if there is no traffic.

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.

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 SHA-1 for maximum

security.

Encryption Key (Only

with ESP)

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 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 Prestige.

Reset

Click Reset to begin configuring this screen afresh.

Table 75 Rule Setup: Manual

LABEL

DESCRIPTION