Vpn Advanced Wizard - Phase 1 Settings - ZyXEL Communications USG40 User Manual

• Remote Access (Client Role) - Connect to an IPSec server. This ZyWALL/USG is the client
(dial-in user) and can initiate the VPN tunnel.

5.3.8 VPN Advanced Wizard - Phase 1 Settings

There are two phases to every IKE (Internet Key Exchange) negotiation – phase 1 (Authentication)
and phase 2 (Key Exchange). A phase 1 exchange establishes an IKE SA (Security Association).
Figure 116 VPN Advanced Wizard: Phase 1 Settings
• Secure Gateway: Any displays in this field if it is not configurable for the chosen scenario.
Otherwise, enter the WAN IP address or domain name of the remote IPSec device (secure
gateway) to identify the remote IPSec device by its IP address or a domain name. Use 0.0.0.0 if
the remote IPSec device has a dynamic WAN IP address.
• My Address (interface): Select an interface from the drop-down list box to use on your
ZyWALL/USG.
• Negotiation Mode: This displays Main or Aggressive:
• Main encrypts the ZyWALL/USG's and remote IPSec router's identities but takes more time to
establish the IKE SA
• Aggressive is faster but does not encrypt the identities.
The ZyWALL/USG and the remote IPSec router must use the same negotiation mode. Multiple SAs
connecting through a secure gateway must have the same negotiation mode.
• Encryption Algorithm: 3DES and AES use encryption. The longer the key, the higher the
security (this may affect throughput). Both sender and receiver must use 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.
AES128 uses a 128-bit key and is faster than 3DES. AES192 uses a 192-bit key, and AES256
uses a 256-bit key.
• Authentication Algorithm: MD5 gives minimal security and SHA512 gives the highest
security. MD5 (Message Digest 5) and SHA (Secure Hash Algorithm) are hash algorithms used to
authenticate packet data. The stronger the algorithm the slower it is.
Chapter 5 Quick Setup Wizards
ZyWALL/USG Series User's Guide
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