Users and Classes

Here you configure the various user and group features of the ftpaccess file (Figure 9-2). For more on this file and its structure, see the ftpaccess man page [http://www.wu-ftpd.org/man/ftpaccess.html].

Figure 9-2: Users and Classes

User classes

Here you define a class of users, and the networks from which they are allowed to log in. Note that the default includes a class all for users of all types ( real, guest, and anonymous) which matches all networks with the *. This option configures the class directive.

Unix users and UIDs to treat as guests and Unix groups and GIDs to treat as guests

Here, you can define users and groups who would ordinarily qualify as real users who will be treated as guests, or anonymous users. In other words, a chroot will be done, and the user will not be permitted to use the USER or PASS commands. The users home directory must be properly set up, as an anonymous FTP directory would be. These two options correspond to the guestuser and guestgroup directives.

Unix users and UIDs not to treat as guests and Unix groups and GIDs not to treat as guests

If your server is configured to treat all users as guests, then you can selectively allow a few users to be treated as real users (i.e., with access to the system directories, and without performing a chroot). These options configure the realuser and realgroup directives.

Unix users to deny (from /etc/ftpusers)

This is simply a list of users to deny access to the server to. This information is drawn from the /etc/ftpusers file. Adding to this list will add to the file. Note that if the next two sets of options are used to precisely control access to the FTP server (i.e., by blocking all access except for explicitly permitted users), then the ftpusers file becomes unnecessary.

Unix users and UIDs to deny and Unix groups and GIDs to deny

Here you can enter any users or groups you would like to deny access to. These options configure the deny-uid and deny-gid directives.

Unix users and UIDs not to deny and Unix groups and GIDs not to deny

These options can be used to negate the above options, if you chose to disallow all access from all users and groups. In this way, you could allow only explicitly configured users to access the server.