When user login to their webmail at http://domain.com/webmail, they can configure the forwarding email option. I have a request from my customer disable that. Anyone can help me solve this issue?
The correct way is to remove it with feature manager: disable "forwarder manager"
Here are all the skins, look in their respective folders, just for your information, but deleting from the skins wont stop someone from manually typing in the address bar.