Check Point UTM-1 Edge User Manual page 267

In the DMZ network's Virtual IP field, type the default gateway IP address
g.
192.168.101.3.
Click the Synchronization radio button next to DMZ.
h.
In the My Priority field, type "60".
i.
The low priority means that Gateway B will be the Passive Gateway.
In the Internet - Primary field, type "20".
j.
Gateway B will reduce its priority by 20, if its Internet connection goes down.
Click Apply.
k.
A success message appears.
Gateway A's priority is 100, and Gateway B's priority is 60. So long as one of Gateway A's
Internet connections is up, Gateway A is the Active Gateway, because its priority is higher
than that of Gateway B.
If both of Gateway A's Internet connections are down, it deducts from its priority 20 (for
the primary connection) and 30 (for the secondary connection), reducing its priority to 50.
In this case, Gateway B's priority is the higher priority, and it becomes the Active
Gateway.
Chapter 8: Configuring High Availability
Sample Implementation on Two Gateways
253