Note: This feature is applicable for PIX 500 series / ASA 5500 Series with software version 7.2(1) or later. For previous versions, the two Internet links need to be terminated on a router in front of the Security appliance, and redundancy needs to be configured on the router because route tracking is not available in these versions.
Use this feature for redundancy or backup purposes only. Outgoing traffic uses the primary Internet service provider (ISP) and then the secondary ISP, if the primary fails.
Use the static route tracking feature on the Security Appliance in order to enable the device to use redundant or backup Internet connections. This feature enables the Security Appliance to continuously query and monitor a remote device/IP address on the Internet Control Message Protocol (ICMP) echo, which in this case is a remote default gateway for ISP. If ICMP monitoring detects that the device is down, then a backup route works instead.