VPN
Setting Up a Remote Access Tunnel for VPN Clients (Client To Gateway)
Cisco Small Business RV0xx Series Routers Administration Guide
144
9
-
Encryption Key:
Enter a key to use to encrypt and decrypt IP traffic. If
you selected DES encryption, enter 16 hexadecimal values. If you
selected 3DES encryption enter 40 hexadecimal values. If you do not
enter enough hexadecimal values, then zeroes will be appended to the
key to meet the required length.
-
Authentication Key:
Enter a key to use to authenticate IP traffic. If you
selected MD5 authentication, enter 32 hexadecimal values. If you
selected SHA1, enter 40 hexadecimal values. If you do not enter enough
hexadecimal values, then zeroes will be appended to the key to meet
the required length.
•
Required fields for IKE with Preshared Key
Enter the settings for Phase 1 and Phase 2. Phase 1 establishes the
preshared keys to create a secure authenticated communication channel. In
Phase 2, the IKE peers use the secure channel to negotiate Security
Associations on behalf of other services such as IPsec.
-
Phase 1 / Phase 2 DH Group:
DH (Diffie-Hellman) is a key exchange
protocol. There are three groups of different prime key lengths: Group 1
- 768 bits, Group 2 - 1,024 bits, and Group 5 - 1,536 bits. For faster speed
but lower security, choose
Group 1
. For slower speed but higher
security, choose
Group 5
. Group 1 is selected by default.
-
Phase 1 / Phase 2 Encryption:
Select a method of encryption for this
phase: DES, 3DES, AES-128, AES-192, or AES-256. The method
determines the length of the key used to encrypt or decrypt ESP
packets. AES-256 is recommended because it is more secure.
-
Phase 1 / Phase 2 Authentication:
Select a method of authentication
for this phase: MD5 or SHA1. The authentication method determines how
the ESP (Encapsulating Security Payload Protocol) header packets are
validated. MD5 is a one-way hashing algorithm that produces a 128-bit
digest. SHA1 is a one-way hashing algorithm that produces a 160-bit
digest. SHA1 is recommended because it is more secure. Make sure that
both ends of the VPN tunnel use the same authentication method.
-
Phase 1 / Phase 2 SA Life Time:
Configure the length of time a VPN
tunnel is active in this phase. The default value for Phase 1 is 28800
seconds. The default value for Phase 2 is 3600 seconds.
-
Perfect Forward Secrecy:
If the Perfect Forward Secrecy (PFS) feature
is enabled, IKE Phase 2 negotiation will generate new key material for IP
traffic encryption and authentication, so hackers using brute force to
break encryption keys will not be able to obtain future IPSec keys.