User's Manual

Chapter 16 IPSec VPN 119
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 Router 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, 6114, and 8192.
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.
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 NULL Encryption to set up a tunnel without encryption. You do not
enter an encryption key with this option.
The Router 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 70 IPSec VPN: Add (continued)
LABEL DESCRIPTION