Cisco ASA 5505 Getting Started Manual page 147

Chapter 10 Scenario: Site-to-Site VPN Configuration
Note
Click Next to continue.
Step 2
78-18003-02
When configuring Security Appliance 2, enter the exact values for each
of the options that you chose for Security Appliance 1. Encryption
mismatches are a common cause of VPN tunnel failures and can slow
down the process.
Implementing the Site-to-Site Scenario
ASA 5505 Getting Started Guide
10-9