Troubleshooting Tip: Value conflicts with system settings error when changing FortiGate 200D NAT Mode to Transparent Mode

Description

This article offers troubleshooting steps for an issue that occurs when FortiGate is configured to NAT Mode and it is changed to transparent mode. The configuration shows the following error:

'value conflicts with system settings'.

Scope

FortiGate 200D when changing NAT Mode to Transparent Mode.

Solution

In order to transform the FortiGate from NAT mode to transparent mode, it is necessary to erase the switch-interface configured by default in the FortiGate:

The following commands must be run:

config system switch-interface

show

config system switch-interface

edit "Switch"

set member "Interface1" "Interface2"

next

end

delete Switch

end

The GUI also makes it possible to change the FortiGate to transparent mode.

To switch to transparent mode in the web-based manager:

• Go to System -> Status.
• Under System Information, select Change beside the Operation Mode.
• Select Transparent.
• Enter the Management IP/Netmask address and the Default Gateway address.
• The default gateway IP address is required to tell the FortiGate unit where to send
  network traffic to other networks.
• Select Apply.