Chapter 17 System Administration : Advanced concepts : Video: Redundant Internet connections using ECMP : Redundant interfaces : Security policies
  
Security policies
When creating security policies, you need to configure duplicate policies to ensure that after traffic fails over WAN1, regular traffic will be allowed to pass through WAN2 as it did with WAN1. This ensures that fail-over will occur with minimal affect to users. For more information on creating security policies see the Firewall Guide.
See Also
Link Health Monitor
Routing
Security policies
Redundant interfaces
Link redundancy and load sharing