User`s guide

Chapter 20 VPN
VMG8924-B10A and VMG8924-B30A Series User’s Guide
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Encryption
Algorithm
Select which key size and encryption algorithm to use in the IKE SA. Choices are:
DES - a 56-bit key with the DES encryption algorithm
3DES - a 168-bit key with the DES encryption algorithm
AES - 128 - a 128-bit key with the AES encryption algorithm
AES - 196 - a 196-bit key with the AES encryption algorithm
AES - 256 - a 256-bit key with the AES encryption algorithm
The Device and the remote IPSec router must use the same key size and encryption
algorithm. Longer keys require more processing power, resulting in increased latency and
decreased throughput.
Integrity
Algorithm
Select which hash algorithm to use to authenticate packet data. Choices are MD5, SHA1.
SHA is generally considered stronger than MD5, but it is also slower.
Select Diffie-
Hellman Group
for Key Exchange
Select which Diffie-Hellman key group you want to use for encryption keys. Choices for
number of bits in the random number are: 768, 1024, 1536, 2048, 3072, 4096.
The longer the key, the more secure the encryption, but also the longer it takes to encrypt
and decrypt information. Both routers must use the same DH key group.
Key Life Time Define the length of time before an IPSec SA automatically renegotiates in this field.
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.
Phase 2
Encryption
Algorithm
Select which key size and encryption algorithm to use in the IKE SA. Choices are:
DES - a 56-bit key with the DES encryption algorithm
3DES - a 168-bit key with the DES encryption algorithm
AES - 128 - a 128-bit key with the AES encryption algorithm
AES - 192 - a 196-bit key with the AES encryption algorithm
AES - 256 - a 256-bit key with the AES encryption algorithm
Select ESP_NULL to set up a tunnel without encryption. When you select ESP_NULL,
you do not enter an encryption key.
The Device and the remote IPSec router must use the same key size and encryption
algorithm. Longer keys require more processing power, resulting in increased latency and
decreased throughput.
Integrity
Algorithm
Select which hash algorithm to use to authenticate packet data. Choices are MD5 and
SHA1. SHA is generally considered stronger than MD5, but it is also slower.
Table 103 Security > IPSec VPN: Add/Edit
LABEL DESCRIPTION