Just checking is it a norm if my ISP dns cannot be validated but it can return back the Server FQDN successfully. See picture below.
I have 2 ISP static fibre broadband. First one is provide by Singtel and another one is Starhub.
When my server is connected to internet with the Singtel, it can validate the Singtel dns with no problem but will not be able to validate the dns provided by Starhub.
If my server is connected to internet with the Starhub, it can validate both Starhub and Singtel dns with no problem.
Does it have anything to do with my Fortigate 100D Firewall?