DNS resolution not working when DNS Server configured to 'Same as Interface IP
Products:
FortiGate v5.2 FortiGate v5.4 FortiGate v5.6
This article provides a solution to DNS resolution not working when DNS Server is configured to “Same as Interface IP”.
DNS resolution can be seen to fail
Solution:
Enable the DNS Database Feature.
Configure a DNS Server for the interface that DNS requests will be sent to.
Set the mode to “Forward to System DNS”.
DNS resolution can now be seen to be successful.