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4.12 Configuring the Users and Groups Module

Like other Webmin modules, Users and Groups has several options that can be configured by clicking on the Module Config link above the lists of users and groups, as shown in Figure 4.9. The options that you can safely change and their meanings are shown in Table 4.2.

04fig09.jpgFigure 4.9. Configuration options for Users and Groups.

Table 4.2. Module Configuration Options

Command to run before making changes

Whatever shell command you enter into this field will be run just before any action is performed, such as adding, deleting, or modifying a user or group. It can be useful for doing things like making a backup copy of the /etc/passwd file before Webmin makes any changes.

The command can determine exactly what Webmin is about to do by checking environment variables, as explained in the Section 4.13 "Before and After Commands".

Command to run after making changes

Like the above option, but this command is run after any action is performed. It can be very useful if you want to have a command run after a user is created in order to setup additional files for that user.

Permissions on new home directories

The octal file permissions on newly created home directories, in the same format as used by the chmod command.

Copy files into new home directories from

Directories or files to copy into the home directory of newly created users, assuming the Copy files to home directory? option is turned on. If any of the paths you enter is a directory, all files and subdirectories in that directory will be copied. This option is usually set to /etc/skel by default, which is a system directory containing files like .cshrc and .profile.

Automatic home directory base

The directory under which users' home directories are usually created. If this option is set, an Automatic option will appear for the Home directory field in the user creation form. If chosen, the home directory will be determined by this option and the Automatic home directory style below.

Automatic home directory style

This option controls the path to a new user's home directory under the base. The most common default option of home/username will make it just a subdirectory under the base, with the same name as the username. So if you were creating a user called jcameron and the home directory base was set to /home, then the resulting home directory would be /home/jcameron.

Other options create subdirectories using the first one or two letters of the username. They can be useful if you have a very large number of users on your system, and want to avoid having thousands of entries in /home.

Lowest UID for new users

When Webmin automatically chooses a user ID for a new user, it will never pick one that is lower than specified in this option. On most systems, normal users have user IDs above 500, and system users have IDs below that.

Lowest GID for new groups

Like the option above, but for group IDs.

Create new group for new users?

If this option is set to Yes when creating a new user, the default action is to create a group of the same name and make it the user's primary group.

Assign same ID to new user and group?

This option only works if the previous one is enabled. If set to Yes when a new group is created for a new user, Webmin will make sure that their UID and GID are the same. This doesn't actually make any difference, but some administrators like it.

Don't use MD5 passwords if missing perl MD5 module?

This option should only be changed to Yes if you run into an error when creating a new user caused by a missing MD5 Perl module.

Check for sendmail alias clashes?

If set to Yes when creating or renaming a user, Webmin will check if there is a Sendmail alias of the same name. This can be useful to prevent the creation of users who would be unable to receive mail due to an alias redirecting it all to another address.

Only delete files owned by user?

If set to Yes when deleting a user, files in the user's home directory that do not belong to him will not be deleted.

Maximum user and group name length

The maximum allowed length for a user or group name. If this is set by default, it is not a good idea to adjust it because your operating system will not recognize longer usernames.

Default group for new users

The default primary group on the new user creation form.

Default secondary groups for new users

A space separated list of secondary groups that will be selected by default on the new user creation form.

Default shell for new users

The default shell on the new user creation form.

Default minimum days for new users

The default number of days before which password changing is not allowed.

Default maximum days for new users

The default number of days after which the password must be changed.

Default warning days for new users

The default number of days before password expiry that the user is warned.

Default inactive days for new users

The default number of days after password expiry that the user is disabled.

Maximum number of users to display

If the number of users or groups on the module's main page exceeds this number, the table of users or groups will be replaced by a search form. You may want to adjust this if the number of users on your system is just over the default limit.

Sort users and groups by

This option controls the ordering of users and groups on the module's main page.

Number of previous logins to display

This option limits the number of recorded logins to display so the table does not become too large on systems that keep an unlimited login history.

Display users and groups by

By default, users and groups are shown on the module's main page in a table with one row per user or group. However, if you change this option to Name only then only the username of each appears, saving a lot of screen space if you have a large number of users.

Changing to Primary group categorized also displays users by username only, but categorized by their primary group.

Conceal plain-text password?

If set to Yes when editing or creating a user, the Normal password field will show only stars instead of the actual password that you enter. Useful if you are worried about people looking over your shoulder when creating users.

Get user and group info from

Even though the module reads and edits system user, group, and password files directly, there will in some cases be users and groups on your system that come from another source, such as NIS. When displaying a user's primary group or the users who are members of a group, Webmin will use the getpw family of system calls by default to get a list of users and groups, instead of reading the user and group files directly.

This is normally the right thing to do, but in some cases it will not work properly or will be very slow. You should only change this option to Files if you are sure that you want the module to never use the getpw functions.

Generate password for new users?

If this option is set to Yes when creating a new user, Webmin will generate a random password for you by default.

Show office and phone details?

Normally, a user's Real name field only contains his name. However, it can also contain additional information such as his office location, home phone, and work phone. These extra fields are displayed by the finger command, and are stored by the system in the real name field of the /etc/passwd file separated by commas.

If you want to be able to edit this additional information separately, set this option to Yes. It will not work well if usernames on your system contain commas in them—like Cameron, Jamie.

Display user email from

This option controls which module is used when the Read Email button is clicked on the user editing page. You should make sure it is set appropriately depending on the mail system you are using because Sendmail and Qmail use different locations and file formats for user mailboxes.

Minimum password length

If set, you will not be able to create or edit users whose plain-text passwords are shorter than this length. This option and the three below also effect the Change Passwords and Cluster Users and Groups modules. They can be useful if you want to delegate user management to someone else, and don't trust the quality of his passwords.

Prevent dictionary word passwords?

If this option is set, passwords that exactly match any word from the dictionary will not be allowed.

Perl regexp to check password against

If set, passwords must match this Perl regular expression. For example, you could enter [0-9] for this option to force all passwords to contain at least one digit.

Prevent passwords containing username?

When this option is set to Yes, passwords that exactly match or contain the user's username will not be allowed.

The other options under the System configuration heading control the files Webmin reads and writes user and group information from and to. Because they are set automatically based on the type of operating system you use, they should not be changed unless you know what you are doing.

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