Technical Tip: PPPoE interface option not available from GUI
Description
This article describes how to configure PPPoE option on the FortiGate.
Scope
FortiGate.
Solution

PPPoE is only configurable in the GUI on desktop FortiGate devices.
1U FortiGate and up have to be configured in the CLI.
From CLI:
config sys interface
(interface)edit port6
(port6)set mode pppoe
(port6)set username pppoe1
(port6)set password fortinet
(port6)end

Configure the PPPoE options from the CLI to be able to see the PPPoE options from the GUI.
Starting FortiOS v7.4.7 and above PPPoE option is available on GUI by default. Also, configuration will be retained in case addressing mode is set to other modes then back to PPPoE.

Note:
After connecting to the PPPoE connection, if the retrieve gateway option is enabled, a default route is automatically created with AD as 5 and priority as 1. This route will take precedence over any previously configured default static route using another Interface and the AD value is higher than 5. This PPPoE Interface AD could be modified on the Interface using the GUI and CLI.
