4.2.5. Detecting Hardware
This step is completely automatic in the vast majority of cases. The installer detects your hardware, and tries to identify the CD-ROM drive used in order to access its content. It loads the modules corresponding to the various hardware components detected, and then “mounts” the CD-ROM in order to read it. The previous steps were completely contained in the boot image included on the CD, a file of limited size and loaded into memory by the BIOS when booting from the CD.
The installer can work with the vast majority of drives, especially standard ATAPI peripherals (sometimes called IDE and EIDE). However, if detection of the CD-ROM reader fails, the installer offers the choice to load a kernel module (for instance from a USB key) corresponding to the CD-ROM driver.
4.2.6. Loading Components
With the contents of the CD now available, the installer downloads all the files necessary to continue with its work. This includes additional drivers for the remaining hardware (especially the network card), as well as all the components of the installation program.
4.2.7. Detecting Network Hardware
This automatic step tries to identify the network card and load the corresponding module. If automatic detection fails, you can manually select the module to load. If no module works, it is possible to load a specific module from a removable peripheral. This last solution is usually only needed if the appropriate driver is not included in the standard Linux kernel, but available elsewhere, such as the manufacturer's website.
This step must absolutely be successful for netinst or businesscard installations, since the Debian packages must be loaded from the network.
4.2.8. Configuring the Network
Eager to automate the process as much as possible, the installer attempts an automatic DHCP network configuration. If this fails, it offers more choices: try again with a normal DHCP configuration, attempt DHCP configuration by declaring the name of the machine, or set up a static network configuration.
This last option requires an IP address, a subnet mask, an IP address for a potential gateway, a machine name, and a domain name.
TIP Configuration without DHCP
If the local network is equipped with a DHCP server that you do not wish to use because you prefer to define a static IP address for the machine during installation, you can add the netcfg/use_dhcp=false option when booting from the CD-ROM. You just need to go to the desired menu entry by pressing the TAB key and add the desired option before pressing the Enter key.
BEWARE Do not improvise
Many local area networks are based on an implicit assumption that all machines can be trusted, and inadequate configuration of a single computer will often perturb the whole network. As a result, do not connect your machine to a network without first agreeing with its administrator on the appropriate settings (for example, the IP address, netmask, and broadcast address).
4.2.9. Configuring the Clock
If the network is available, the system's internal clock is updated (in a one-shot way) from an NTP server. This way the timestamps on logs will be correct from the first boot. For them to remain consistently precise over time, an NTP daemon needs to be set up after initial installation (see Section 8.9.2, “Time Synchronization”).
4.2.10. Administrator Password
The super-user root account, reserved for the machine's administrator, is automatically created during installation; this is why a password is requested. A confirmation (or two identical entries) will prevent any entry error which would later be difficult to amend.
Figure 4.5. Administrator Password
SECURITY Administrator password
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).