Access-control file for ftpd
/etc/ftpchroot
The /etc/ftpchroot file lists the users who should have their session's root directory changed (using chroot()). The root directory is changed accordingly:
If this file doesn't exist, the root directory change isn't performed.
The syntax is similar to /etc/ftpusers, except that the class argument is ignored:
userglob[:groupglob][@host] [directive]
Refer to /etc/ftpusers for detailed descriptions of each element.
If there's a positive match, the session's root directory is changed. No further comparisons are attempted after the first successful match. This syntax is backward-compatable with the old syntax.