I'm new in term of linux environment and I really want to know if my problem have a solution or not.

So, I have the horde groupware installed, and the users could send email normally, but I want to know if I could prevent them of using the option to add attachment ? I change some files of the groupware in order to show the message ( please use filezilla to send attachment!) but if I configure the user on thunderbird, he could send the attachment.

so, in fact I chnage this from the client side, how can I do the same from the server side, so whatever the users use mail client, they will have the same behavior (alert them to use the Filezilla)

Thanks

I suggest finding out if there is a way to limit the size of attachments on the server side - probably is. Then set it to 10 bytes ( or some absurd low value ) so it will choke on the attachment and reject it.

Not elegant, but should work

Thanks for your quick answer ceyx, well, I don't need to reject all the email, in case the user write some text and later try to attach some file(s) to the mail, he must have the message saying ( use filezilla...) but he could send the text without any problem.

As i mention before, from the groupware it works fine, but I wanna make it from the server side, in this case the user won't be able to attach files regardless the mail client he use :/