I think the following may help you
The syntax for the DefaultRoot directive is:
DefaultRoot DIRECTORY USER(S)
You can make DefaultRoot entries at the bottom of the proftpd.conf file.
Example 1: To restrict the user ‘myname’ to their home directory, you would make the following addition to the proftpd.conf file:
DefaultRoot ~ myname
The ~ represents the home directory of any user, so this would restrict the user myname to their home directory when in FTP.
Example 2 - To restrict the user myname to a vhost directory, the following entry could be made:
DefaultRoot /home/unixname/domain.url/html/ myname
You need to restart ProFTP when changed