The Debian Administrator's Handbook

The root user's password should be long (6 characters or more) and impossible to guess. Indeed, any computer (and a fortiori any server) connected to the Internet is regularly targeted by automated connection attempts with the most obvious passwords. Sometimes it may even be subject to dictionary attacks, in which many combinations of words and numbers are tested as password. Avoid using the names of children or parents, dates of birth, etc.: many of your co-workers might know them, and you rarely want to give them free access to the computer in question.

These remarks are equally applicable for other user passwords, but the consequences of a compromised account are less drastic for users without administrative rights.

If inspiration is lacking, do not hesitate to use password generators, such as pwgen (in the package of the same name).

4.2.11. Creating the First User

Debian also imposes the creation of a standard user account so that the administrator doesn't get into the bad habit of working as root. The precautionary principle essentially means that each task is performed with the minimum required rights, in order to limit the damage caused by human error. This is why the installer will ask for the complete name of this first user, their username, and their password (twice, to prevent the risk of erroneous input).

Figure 4.6. Name of the first user

4.2.12. Detecting Disks and Other Devices

This step automatically detects the hard drives on which Debian may be installed. They will be presented in the next step: partitioning.

4.2.13. Starting the Partitioning Tool

CULTURE Uses of partitioning

Partitioning, an indispensable step in installation, consists in dividing the available space on the hard drives (each subdivision thereof being called a “partition”) according to the data to be stored on it and the use for which the computer is intended. This step also includes choosing the filesystems to be used. All of these decisions will have an influence on performance, data security, and the administration of the server.

The partitioning step is traditionally difficult for new users. It is necessary to define the various portions of the disks (or “partitions”) on which the Linux filesystems and virtual memory (swap) will be stored. This task is complicated if another operating system that you want to keep is already on the machine. Indeed, you will then have to make sure that you do not alter its partitions (or that you resize them without causing damage).

Fortunately, the partitioning software has an “guided” mode which recommends partitions for the user to make — in most cases, you can simply validate the software's suggestions.

Figure 4.7. Choice of partitioning mode

The first screen in the partitioning tool offers the choice of using an entire hard drive to create various partitions. For a (new) computer which will solely use Linux, this option is clearly the simplest, and you can choose the option “Guided - use entire disk”. If the computer has two hard drives for two operating systems, setting one drive for each is also a solution that can facilitate partitioning. In both of these cases, the next screen offers to choose the disk where Linux will be installed by selecting the corresponding entry (for example, “SCSI3 (0,0,0) (sda) - 12.9 GB ATA VBOX HARDDISK”). You then start guided partitioning.

Figure 4.8. Disk to use for guided partitioning

Guided partitioning can also set up LVM logical volumes instead of partitions (see below). Since the remainder of the operation is the same, we will not go over the option “Guided - use entire disk and set up LVM” (encrypted or not).

In other cases, when Linux must work alongside other already existing partitions, you need to choose manual partitioning.

4.2.13.1. Guided partitioning

The guided partitioning tool offers three partitioning methods, which correspond to different usages.

Figure 4.9. Guided partitioning

The first method is called “All in one partition”. The entire Linux system tree is stored in a single filesystem, corresponding to the root / directory. This simple and robust partitioning fits perfectly for personal or single-user systems. In fact, two partitions will be created: the first will house the complete system, the second the virtual memory (swap).

The second method, “Separate /home/ partition”, is similar, but splits the file hierarchy in two: one partition contains the Linux system (/), and the second contains “home directories” (meaning user data, in files and subdirectories available under /home/).