SonicWALL Internet Security Appliances - Manual (Page 182)

SonicWALL VPN Page 183
- Strong Encrypt and Authenticate (ESP 3DES HMAC SHA1) - uses 168-bit 3DES encryption and
HMAC SHA1 authentication. 3DES is an extremely secure encryption method, and HMAC SHA1
is used to verify integrity. This method significantly impacts the data throughput of the
SonicWALL.
- Strong Encrypt and Authenticate (ESP 3DES HMAC MD5) - uses 168-bit 3DES encryption and
HMAC MD5 authentication. 3DES is an extremely secure encryption method, and HMAC MD5 is
used to verify integrity. This method significantly impacts the data throughput of the SonicWALL.
- Strong Encrypt and Authenticate (ESP DES HMAC SHA1) - uses 56-bit DES encryption and
HMAC SHA1 authentication.
- Strong Encrypt and Authenticate (ESP DES HMAC MD5) - uses 56-bit DES encryption and
HMAC MD5 authentication. This method impacts the data throughput of VPN communications.
SonicWALL VPN client supports this method.
- Strong Encrypt and Authenticate (ESP AES-128 HMAC MD5) - uses 128-bit AES encryption and
HMAC MD5 authentication.
- Strong Encrypt and Authenticate (ESP AES-128 HMAC SHA1) - uses 128-bit AES encryption and
HMAC SHA1 authentication.
• Shared Secret - an alphanumeric key is automatically generated as the Shared Secret. The
Shared Secret is not exported with the VPN Client Configuration File. The Shared Secret must
be distributed by the SonicWALL administrator.
Security Policy Settings for IKE using Pre-shared Secret
• Exchange - select Main Mode or Aggressive Mode. Main Mode requires six one-way messages
between the peers and Aggressive Mode requires only three one-way messages making
Aggressive Mode a little faster when establishing the connection. Selecting Aggressive Mode
forces the SonicWALL appliance to use Aggressive Mode to establish the VPN tunnel even if the
SonicWALL has a static IP address. Aggressive Mode is useful when the SonicWALL is located
behind another NAT device.
• Phase 1 DH Group - Diffie-Hellman (DH) key exchange (a key agreement protocol) is used during
phase 1 of the authentication process to establish pre-shared keys. Groups 1, 2, 5 use Modular-
Exponential with different prime lengths as listed below:
If network speed is preferred, select Group 1. If network security is preferred, select Group 5.
To compromise between network speed and network security, select Group 2.
• SA Life time (secs) - allows you to configure the length of time a VPN tunnel is active. The default
value is 28800 seconds (eight hours). You can configure up to 2,500,000 seconds (28.9 days).
Group Descriptor
Prime Size
(bits)
Group 1 768
Group 2 1024
Group 5 1536