AudioCodes Mediant 3000, User Manual

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User's Manual 150 Document #: LTRT-89729
Mediant 3000
IKE is used to obtain the Security Associations (SA) between peers (the device and the
application it’s trying to contact). The SA contains the encryption keys and profile used by
IPSec to encrypt the IP stream. IKE negotiation comprises the following two phases:

Main Mode (creates a secured channel for the Quick mode by obtaining a "master"
encryption key, without any prior keys, and authenticates the peers to each other):
•
SA negotiation: The peers negotiate their capabilities using up to four proposals.
Each proposal includes the Encryption method, Authentication algorithm, and the
Diffie-Hellman (DH) group. The master key’s lifetime is also negotiated.
•
Key exchange (DH): The DH protocol creates the master key. DH requires both
peers to agree on certain mathematical parameters, known as the "group".
•
Authentication: The two peers authenticate one another using a pre-shared key
configured in the IP Security Associations Table or by using certificate-based
authentication.

Quick Mode (creates the encrypted IPSec tunnel once initial security is set up):
•
SA negotiation: An IPSec SA is created by negotiating encryption and
authentication capabilities using the same proposal mechanism as in Main mode.
•
Key exchange: A symmetrical key is created for encrypting IPSec traffic; the
peers communicate with each other in encrypted form, secured by the previously
negotiated "master" key.
IKE specifications summary:

Authentication methods: pre-shared key or certificate-based authentication

Main mode supported for IKE Phase 1

DH group 1 or group 2

Encryption algorithms: Data Encryption Standard (DES), Advanced Encryption
Standard (AES), and 3DES

Hash algorithms: SHA1 and MD5
IPSec is responsible for securing the IP traffic. This is accomplished by using the
Encapsulation Security Payload (ESP) protocol to encrypt (and decrypt) the IP payload.
This is configured in the IPSec Security Association table, which defines the IP peers to
which IPSec security is applied.
IPSec specifications summary:

Transport and Tunneling Mode

Encapsulation Security Payload (ESP) only

Encryption algorithms: AES, DES, and 3DES

Hash types: SHA1 and MD5
12.3.1 Enabling IPSec
To enable IKE and IPSec processing, you must enable the IPSec feature, as described
below.

To enable IPSec:
1. Open the General Security Settings page (Configuration tab > VoIP menu > Security >
General Security Settings).
Figure 12-3: Enabling IPSec
2. Set the 'Enable IP Security' parameter to Enable.
3. Click Submit, and then reset the device with a flash burn.