FortiOS has replacement messages that are HTML and text files. These messages can be customized to meet user requirements. The content can be modified, and images can be added.
The Replacement Messages page has two views. Simple View (the default view) shows the most commonly used replacement messages. Extended View shows the entire list and all replacement message categories.
Go to System > Replacement Messages.
Select a replacement message and click Edit.
If the message you want to edit is not visible, click Extended View in the upper right-hand corner of the top menu.
Edit the HTML code.
The message is visible on the left alongside the HTML code on the right. The message view updates in real-time as you edit the content.
When adding a variable to the code, right-click and select Insert Tag or type
%%to view a list of the available variables, or start typing the variable name then press Enter or TAB to auto-complete the variable name.
Click Restore Defaults to return to the original message and code base.
For example, to modify the Traffic Quota Limit Exceeded Page message:
config system replacemsg traffic-quota "per-ip-shaper-block" set buffer "<html> <head> <title> Traffic Quota Control </titl