Wireless Firewall Router User's Guide

P-335 Series User’s Guide
181 Chapter 13 VPN Screens
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. The Prestige's
authentication algorithm should be identical to the secure remote gateway.
MD5 (Message Digest 5) and SHA1 (Secure Hash Algorithm) are hash
algorithms used to authenticate the source and integrity of packet data. The
SHA1 algorithm is generally considered stronger than MD5, but is slower.
Select SHA-1 for maximum security.
SA Life Time Define the length of time before an IKE SA automatically renegotiates in this
field. It may range from 60 to 3,000,000 seconds (almost 35 days). A short SA
Life Time increases security by forcing the two VPN gateways to update the
encryption and authentication keys. However, every time the VPN tunnel
renegotiates, all users accessing remote resources are temporarily
disconnected.
Key Group You must choose a key group for phase 1 IKE setup. DH1 (default) refers to
Diffie-Hellman Group 1 a 768 bit random number. DH2 refers to Diffie-Hellman
Group 2 a 1024 bit (1Kb) random number.
Pre-Shared Key Type your pre-shared key in this field. A pre-shared key identifies a
communicating party during a phase 1 IKE negotiation. It is called "pre-
shared" because you have to share it with another party before you can
communicate with them over a secure connection.
IKE Phase 2 A phase 2 exchange uses the IKE SA established in phase 1 to negotiate the
SA for IPSec.
Encapsulation Mode Select Tunnel mode or Transport mode from the drop down list-box. The
Prestige's encapsulation mode should be identical to the secure remote
gateway.
IPSec Protocol Select ESP or AH from the drop-down list box. The Prestige's IPSec Protocol
should be identical to the secure remote gateway. The ESP (Encapsulation
Security Payload) protocol (RFC 2406) provides encryption as well as the
authentication offered by AH. If you select ESP here, you must select options
from the Encryption Algorithm and Authentication Algorithm fields (described
below). The AH protocol (Authentication Header 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.
Encryption Algorithm The encryption algorithm for the Prestige and the secure remote gateway
should be identical. 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.
Table 73 Advanced Rule Setup (continued)
LABEL DESCRIPTION