Virtual Private Server User Guide

User and Group Management

Group Management

Each file and directory on your server is owned by both a user and a group. 

Different users are often grouped together into user groups. For example, when 

you add a virtual host to your VPS server with the vaddvhost command, a user 

group with the name of the virtual host is created for you automatically. The 

purpose of such a user group is to allow multiple users to have access to files, 

directories, or other resources. On the VPS Root product, you can create an 

arbitrary number of user groups by editing the /etc/group file as the superuser.

Special User Groups and Super Commands

There are a number of powerful user groups that are enabled to perform various 

administrative tasks such as manage a single Web site, manage your entire Web 

or mail server, or even manage the entire virtual server in the same way that you 

do. These groups are called special user groups. You can grant users very 

powerful access rights by making them members of these special user groups. 

Users that are members of these special user groups have access to modify key 

files on the system, and can run powerful administrative commands that we call 

super commands.

Warning! It is critical that you do not make a user a member of one 

of these special user groups unless you have a specific need to do 

so and you trust the user completely. A user who is empowered to 

use ANY of the super commands can cause a great deal of damage 

to your system if they choose to do so. The special user groups are 

available for convenience only. Do not assume that a user who is a 

member of a special user group is limited only to commands and file 

access that is provided by membership in that group. It is not 

impossible for a user who is a member of a special user group to 

find a way to make himself a member of another, or gain additional 

control of the server through some other means. 

The following is a list of the special user groups, the super commands they are 

allowed to execute, and the files and directories that they have special write 

access to. The user account that is initially set up for you when you order your 

VPS server is sometimes referred to as the administrative user. The 

administrative user derives its power from being a member of all of the special 

user groups and therefore has access to all of the super commands. 

Technical Training Department

August 2004

2 12