FTP user limitation

Hello! I need your help, guys.
I want to make a ftp for the members of my forum, but i want to block the option to delete/rename/cut files, in this case, just add more files.

How i can do it? What’s the permission that i need change? If I’m going to need use ssh please tell me the exactly code.

Thanks in advance.

This is probably not a good use case for FTP. I would recommend that you investigate alternatives.

That being said, you can control FTP permissions on an anonymous FTP service. Please note that anonymous FTP requires that your site have a Unique IP allocated to it.