Deceptive url prevention can be set in your Antispam Configuration from the e-securemail interface.
1. Log on to https://www.security-mail.net
2. Enter your administrator login
3. Navigate to Configuration => Domain filtering
In the "Antispoofing & warning banner" customization panel
Click on Active to activate the warning banner
Note: You can set the warning banner for a filter group if you don't want it to apply to the whole domain.
Go to the filter group.
Customization option :
"It is possible to customize both the color and the text displayed in the prevention banner. You can choose from several colors, including yellow, orange, red and gray."