To ensure high availability of internet access when deploying a pair of Cisco Secure Firewall Threat Defense (FTD) devices managed by Cisco Secure Firewall Management Center (FMC), the following features must be deployed:

Route Tracking:This feature monitors the reachability of a specified target (such as an external IP address) through the configured routes. If the route to the target is lost, the FTD can dynamically adjust the routing to use an alternate path, ensuring continuous internet access.

SLA Monitor:Service Level Agreement (SLA) monitoring works alongside route tracking to continuously verify the status and performance of the internet links. If the SLA for one of the ISP links fails (indicating the link is down or underperforming), the FTD can switch traffic to the secondary ISP link.

Steps to configure:

In FMC, navigate toDevices > Device Management.

Select the FTD device and configure route tracking to monitor the ISP links.

Configure SLA monitors to continuously check the health and performance of the internet circuits.

These configurations ensure that internet access remains available to users even if one of the ISPs goes down.