BETA DRAFT - CISCO CONFIDENTIAL
7-3
Cisco1800 Series Integrated Services Routers (Fixed) Software Configuration Guide
OL-6426-02
Chapter7 Configuring VPNs Using an IPSec Tunnel and Generic Routing Encapsulation
Configure a VPN
Configure a VPN
Perform the following tasks to configure a VPN over an IPSec tunnel:
•Configure the IKE Policy
•Configure Group Policy Information
•Enable Policy Lookup
•Configure IPSec Transforms and Protocols
•Configure the IPSec Crypto Method and Parameters
•Apply the Crypto Map to the Physical Interface

Configure the IKE Policy

Perform these steps to configure the Internet Key Exchange (IKE) policy, beginning in global
configuration mode:
Command or Action Purpose
Step1 crypto isakmp policy priority
Example:
Router(config)# crypto isakmp policy 1
Router(config-isakmp)#
Creates an IKE policy that is used during IKE
negotiation. The priority is a number from 1 to
10000, with 1 being the highest.
Also enters Internet Security Association Key and
Management Protocol (ISAKMP) policy
configuration mode.
Step2 encryption {des | 3des | aes | aes 192 | aes 256}
Example:
Router(config-isakmp)# encryption 3des
Router(config-isakmp)#
Specifies the encryption algorithm used in the IKE
policy.
The example uses 168-bit Data Encryption
Standard (DES).
Step3 hash {md5 | sha}
Example:
Router(config-isakmp)# hash md5
Router(config-isakmp)#
Specifies the hash algorithm used in the IKE
policy.
The example specifies the Message Digest 5
(MD5) algorithm. The default is Secure Hash
standard (SHA-1).
Step4 authentication {rsa-sig | rsa-encr | pre-share}
Example:
Router(config-isakmp)# authentication
pre-share
Router(config-isakmp)#
Specifies the authentication method used in the
IKE policy.
The example uses a pre-shared key.