DGFV338 ProSafe Wireless ADSL Modem VPN Firewall Router Reference Manual
5-8
Virtual Private Networking
v1.0, May 2008
•
Encr
. Encryption Algorithm used for the IKE SA. The default setting using the VPN Wizard is
3DES. (This setting must match the Remote VPN.)
•
Auth
. Authentication hashing algorithm used for the IKE SA. The default setting using the
VPN Wizard is SHA1. (This setting must match the Remote VPN.)
•
DH
. Diffie-Hellman Group. The Diffie-Hellman algorithm is used when exchanging keys. The
DH Group sets the number of bits. The VPN Wizard default setting is Group 2. (This setting
must match the Remote VPN.)
To gain a more complete understanding of the encryption, authentication, and DH algorithm
technologies, see
Appendix B, “Related Documents”
for a link to the NETGEAR website.
VPN Policy
You can create two types of VPN Policies. When using the VPN Wizard to create a VPN policy,
only the Auto method is available.
•
Manual
. All settings (including the keys) for the VPN tunnel are manually input at each end
(both VPN Endpoints). No third party server or organization is involved.
•
Auto
. Some parameters for the VPN tunnel are generated automatically by using the IKE
(Internet Key Exchange) protocol to perform negotiations between the two VPN Endpoints
(the Local ID Endpoint and the Remote ID Endpoint).
In addition, a CA (Certificate Authority) can also be used to perform authentication (see
“Certificate Authorities” on page 5-23
). To use a CA, each VPN gateway must have a Certificate
from the CA. For each Certificate, there is both a “Public Key” and a “Private Key”. The “Public
Key” is freely distributed, and is used to encrypt data intended for the receiver. The receiver then
uses its “Private Key” to decrypt the data (without the Private Key, decryption is impossible). CAs
can be beneficial since using them reduces the amount of data entry required on each VPN
Endpoint.
Managing VPN Policies
The VPN Policies screen allows you to add additional policies—either Auto or Manual—and to
manage the VPN policies already created. You can edit policies, enable or disable policies, or
delete them entirely. The rules for VPN policy use are:
1. Traffic covered by a policy will automatically be sent via a VPN tunnel.
2. When traffic is covered by two or more policies, the first matching policy will be used. (In this
situation, the order of the policies is important. However, if you have only one policy for each
remote VPN Endpoint, then the policy order is not important.)
3. The VPN tunnel is created according to the parameters in the SA (Security Association).
