FortiGate: a specific WAN interface fail with "execute ping"

[SonHuynh]

Hi,

I have 3 WAN interfaces:

WAN1: PPPOE

WAN2: Trunk port (with 2 subInterfaces + Public IPs)

WAN3: PPPOE

When all of the WANs are functioning properly, I use the CLI on the FortiGate:

"execute ping-options source <IP of WAN interface>"

and try

"execute ping 8.8.8.8"

Then, only WAN1 and WAN3 are successful. WAN2 fails.

I also tried pinging from a PC inside the internal network, and it applied an SD-WAN rule to route all traffic through WAN2, which was successful.

I don't know what is going on.

Could anyone help with troubleshooting the case?"

[DPadula]

Definitely is not the link but the SDWAN configuration when you include WAN2.

Have a look on this link, it will help you to understand the SDWAN settings:

https://community.fortinet.com/t5/FortiGate/Technical-Tip-Multiple-default-routes-where-SD-WAN-rules...

If you still facing the issue after apply the solution on the link above I suggest you to raise a support case our TAC. We will contact you for a remote session to investigate the issue.

Regards

DPadula

[Ade_23]

Hi @SonHuynh While you have 2 subnets on your side, the isp may be treating both as 1 subnet. Can you confirm with the isp if that is the case?