ZyXEL Communications wireless n gigbit router zyxel 226, Encryption and Authentication Algorithms

Chapter 15 IPSec VPN

An IPSec SA can be set to keep alive Normally, the NBG-460N drops the IPSec SA when the life time expires or after two minutes of outbound traffic with no inbound traffic. If you set the IPSec SA to keep alive , the NBG-460N automatically renegotiates the IPSec SA when the SA life time expires, and it does not drop the IPSec SA if there is no inbound traffic.

Note: The SA life time and keep alive settings only apply if the rule identifies the remote IPSec router by a static IP address or a domain name. If the Secure Gateway Address field is set to 0.0.0.0, the NBG-460N cannot initiate the tunnel (and cannot renegotiate the SA).

Encryption and Authentication Algorithms

In most NBG-460Ns, you can select one of the following encryption algorithms for each proposal. The encryption algorithms are listed here in order from weakest to strongest.

•Data Encryption Standard (DES) is a widely used (but breakable) method of data encryption. It applies a 56-bit key to each 64-bit block of data.

•Triple DES (3DES) is a variant of DES. It iterates three times with three separate keys, effectively tripling the strength of DES.

You can select one of the following authentication algorithms for each proposal. The algorithms are listed here in order from weakest to strongest.

•MD5 (Message Digest 5) produces a 128-bit digest to authenticate packet data.

•SHA1 (Secure Hash Algorithm) produces a 160-bit digest to authenticate packet data.

Private DNS Server

In cases where you want to use domain names to access Intranet servers on a remote private network that has a DNS server, you must identify that DNS server. You cannot use DNS servers on the LAN or from the ISP since these DNS servers cannot resolve domain names to private IP addresses on the remote private network.

The following figure depicts an example where one VPN tunnel is created from an NBG-460N at branch office (B) to headquarters (HQ). In order to access

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NBG-460N User’s Guide