I installed and configured proftp on Debian using this howto and it works nicely.
Effectively, the changes to the config are:
[...]
UseIPv6 off
[...]
<Global>
RootLogin off
RequireValidShell off
</Global>
DefaultRoot ~
<Limit LOGIN>
DenyGroup !ftpgroup
</Limit>
and the permission of the user directory are
addgroup ftpgroup
adduser otropload -shell /bin/false -home /ftpshare
chmod -R 1777 /ftpshare/
but I would like to have one change:
I would like to have this user to be an upload only user who does not see the files but can upload new files. I assume this is possible by changing permissions, but I have no idea which ones.
So my question:
How can I configure proftpd or the permissions of the users home directory so that a user can only upload to the ftp server and does not see existing files?