MitraStar Movistar GPT-2541GNAC, User Manual

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Chapter 16 IPSec VPN 120
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.
The following fields display if you select Manual in the Key Exchange Method field.
Perfect Forward
Secrecy (PFS)
Select whether or not to enable Perfect Forward Secrecy (PFS). Both routers
must enable it or disable it.
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 - AES-CBC encryption. CBC creates message authentication code from a
block cipher.
Encryption Key This field is applicable when you select an Encryption Algorithm.
Enter the encryption key, which depends on the encryption algorithm.
DES - type a unique key 16 hexadecimal characters long.
3DES - type a unique key 48 hexadecimal characters long.
AES - type a unique key 32, 48, or 64 hexadecimal characters long.
Authentication
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.
Authentication Key Enter the authentication key, which depends on the authentication algorithm.
MD5 - type a unique key 32 hexadecimal characters long
SHA1 - type a unique key 40 hexadecimal characters long
SPI Type a unique SPI (Security Parameter Index) in hexadecimal characters.
The SPI is used to identify the Router during authentication.
The Router and remote IPSec router must use the same SPI.
Apply/Save Click this button to save your changes.
Table 70 IPSec VPN: Add (continued)
LABEL DESCRIPTION