SD-WAN not generating default gateways for all links

Hi everyone,

I'm currently configuring SD-WAN on a FortiGate device, and I’ve noticed that the default routes (0.0.0.0/0) are not being generated automatically for all WAN interfaces as expected.

I have four WAN links added as SD-WAN members, and SD-WAN is enabled. However, when I check the routing table, I only see two default routes. I was expecting FortiGate to automatically generate a default route per interface when SD-WAN is active.

Here’s what I’ve done so far:

• Added all interfaces to the SD-WAN zone

• Assigned gateways for each member (both working members are configured via DHCP)

• Checked SD-WAN rules and performance SLA (removed them just for debugging)

• Verified that all interfaces are up and reachable (adding a static route for my source IP, just to check ping over internet)

Still, the routing table doesn’t reflect all default gateways. I suspect I might be missing a step or perhaps some specific configuration is required to force the routes.

Has anyone faced this issue before? Should I manually add static default routes, or is there something else I should configure to make FortiGate generate them automatically via SD-WAN?

Thanks in advance!

SDWAN definition

config system sdwan
set status enable
set load-balance-mode measured-volume-based
config zone
edit "virtual-wan-link"
next
end
config members
edit 1
set interface "ha1"
next
edit 2
set interface "wan2"
set gateway 200.XXX.XXX.XXX #This is not working
next
edit 4
set interface "dmz"
next
edit 5
set interface "npu0_vlink1"
set gateway 200.XXX.XXX.XXX #This is not working
next
end
end

Route List

get router info routing-table all

Routing table for VRF=0
S* 0.0.0.0/0 [5/0] via 186.XXX.XXX.XXX, dmz, [1/0]
[5/0] via 200.XXX.XXX.XXX, ppp3, [1/0]

Members status

diagnose sys sdwan member

Member(1): interface: ha1(ppp3), flags=0x0 , gateway: 200.51.241.1, priority: 1 1024, weight: 0
Config volume ratio: 1, last reading: 120006119865B, overload volume 24733MB
Member(2): interface: wan2, flags=0x0 , gateway: 200.85.183.173, priority: 1 1024, weight: 25
Config volume ratio: 1, last reading: 27051273B, volume room 25MB
Member(4): interface: dmz, flags=0x0 , gateway: 186.139.244.1, priority: 1 1024, weight: 0
Config volume ratio: 1, last reading: 225877796055B, overload volume 27920MB
Member(5): interface: npu0_vlink1, flags=0x0 , gateway: 200.5.96.209, priority: 1 1024, weight: 25
Config volume ratio: 1, last reading: 3489802572214B, volume room 25MB