I found this in my notes…
The gateway fail-safe feature allows further redundancy between a failover pair of BIG-IP systems that point to different gateways. The gateway fail-safe feature allows each BIG-IP system to monitor the upstream gateway to which they are connected. If the gateway is marked down, the BIG-IP system can failover to its partner system to prevent further disruption to traffic.
Copy and paste the following commands:
b monitor ICMP_GWFailsafe ‘{defaults from gateway_icmpinterval 2timeout 7}’b pool gateway_pool_unit1 ‘{min up members enablemin up members 1min up members failoverunit 1monitor all ICMP_GWFailsafemembers x.x.x.x:any {}}’b pool gateway_pool_unit2 ‘{min up members enablemin up members 1min up members failoverunit 2monitor all ICMP_GWFailsafemembers x.x.x.x:any {}}’<CR>
Note: Replace x.x.x.x with the IP address of your egress interface of your upstream router.
Save the gateway fail-safe pool configurations by typing the following command:
bigpipe save
Synchronize the configuration between the systems by typing the following command:
bigpipe config sync min
Reload the system configuration by typing the following command:
bigpipe load
To verify that the gateway fail-safe is now enabled, type the following command:
bigpipe ha table
You should see the pool min up member line, which indicates that the gateway fail-safe feature is enabled on the system.