Recommendation about this feature
This feature works only between the following platforms:
•Two Cisco ASA 5500 series security appliances
•A Cisco ASA 5500 series security appliance and a Cisco VPN 3000 concentrator
•A Cisco ASA 5500 series security appliance and a security appliance running Cisco PIX security appliance software v7.0, or higher
A backup Site-to-Site tunnel between a Cisco ASA and a 3rd party device is not supported.
More information about this feature on the link below
http://www.cisco.com/c/en/us/td/docs/security/asa/asa82/command/reference/cmd_ref/c5.html#wp2238363
Requirements:
Cisco ASA firewall running 8.3 code or above
Scenario
On this example we are going to use the following topology as our case scenario:
Configuration required
ASA 1 Configuration
ASA1(config)#crypto map S2S-tunnel 1 set transform-set esp-3des-sha
ASA1(config)#crypto map S2S-tunnel 1 match address ASA1toASA2
ASA1(config)#crypto map S2S-tunnel 1 set connection-type originate-only
ASA1(config)#crypto map S2S-tunnel 1 set peer 2.2.2.2 3.3.3.3
ASA1(config)#crypto map S2S-tunnel interface outside
ASA 2 Configuration
ASA2(config)#crypto map S2S-tunnel 1 set transform-set esp-3des-sha
ASA2(config)#crypto map S2S-tunnel 1 match address ASA2toASA1
ASA2(config)#crypto map S2S-tunnel 1 set connection-type answer-only
ASA2(config)#crypto map S2S-tunnel 1 set peer 1.1.1.1
ASA2(config)#crypto map S2S-tunnel interface outside
ASA 3 Configuration
ASA3(config)#crypto map S2S-tunnel 1 set transform-set esp-3des-sha
ASA3(config)#crypto map S2S-tunnel 1 match address ASA3toASA1
ASA3(config)#crypto map S2S-tunnel 1 set connection-type answer-only
ASA3(config)#crypto map S2S-tunnel 1 set peer 1.1.1.1
ASA3(config)#crypto map S2S-tunnel interface outside
Hope it helps
-Randy-