This section only applies if a network card is to be configured.
Starting with version 209, systemd ships a network configuration daemon called systemd-networkd which can be used for basic network configuration.
Configuration files for systemd-networkd can be placed in
/etc/systemd/network. Note that files
/etc/systemd/network have higher
priority than the ones in
There are three types of configuration files:
.network files. For detailed
explanation about contents of the mentioned configuration files,
systemd-network(5) manual pages.
Udev may assign network card interface names based on system physical characteristics such as enp2s1. If you are not sure what your interface name is, you can always run ip link after you have booted your system.
The command below creates a basic configuration file for Static IP setup:
cat > /etc/systemd/network/10-static-eth0.network << "EOF"
[Match] Name=eth0 [Network] Address=192.168.0.2/24 Gateway=192.168.0.1 DNS=192.168.0.1EOF
More than one DNS entry can be specified in the configuration file.
If the system is going to be connected to the Internet, it will
need some means of Domain Name Service (DNS) name resolution to
resolve Internet domain names to IP addresses, and vice versa. This
is best achieved by placing the IP address of the DNS server,
available from the ISP or network administrator, into
desired, create it by running the following command:
cat > /etc/resolv.conf << "EOF"
# Begin /etc/resolv.conf domainEOF
<Your Domain Name>nameserver
<IP address of your primary nameserver>nameserver
<IP address of your secondary nameserver># End /etc/resolv.conf
domain statement can be omitted or
replaced with a
search statement. See
the man page for resolv.conf for more details.
<IP address of the
nameserver> with the IP address of the DNS most
appropriate for the setup. There will often be more than one entry
(requirements demand secondary servers for fallback capability). If
you only need or want one DNS server, remove the second
nameserver line from the
file. The IP address may also be a router on the local network.
The Google Public IPv4 DNS addresses are 18.104.22.168 and 22.214.171.124.
When using systemd-networkd for network
configuration, another daemon, systemd-resolved, is responsible
for creating the
file. It is, however, placed in a non-standard location which is
writable since early boot, so it is necessary to create a symlink
to it by running the following command:
ln -sfv /run/systemd/resolve/resolv.conf /etc/resolv.conf
This is required if you are specifying DNS entries in
.network files or using the built in DHCP client
to obtain DNS addresses.
During the boot process, the file
/etc/hostname is used for establishing the
/etc/hostname file and
enter a hostname by running:
<lfs>" > /etc/hostname
<lfs> needs to be
replaced with the name given to the computer. Do not enter the
Fully Qualified Domain Name (FQDN) here. That information is put in
Decide on the IP address, fully-qualified domain name (FQDN), and
possible aliases for use in the
/etc/hosts file. The syntax is:
IP_address myhost.example.org aliases
Unless the computer is to be visible to the Internet (i.e., there is a registered domain and a valid block of assigned IP addresses—most users do not have this), make sure that the IP address is in the private network IP address range. Valid ranges are:
Private Network Address Range Normal Prefix 10.0.0.1 - 10.255.255.254 8 172.x.0.1 - 172.x.255.254 16 192.168.y.1 - 192.168.y.254 24
x can be any number in the range 16-31. y can be any number in the range 0-255.
A valid private IP address could be 192.168.1.1. A valid FQDN for this IP could be lfs.example.org.
Even if not using a network card, a valid FQDN is still required. This is necessary for certain programs to operate correctly.
/etc/hosts file by
cat > /etc/hosts << "EOF"
# Begin /etc/hosts (network card version) 127.0.0.1 localhost ::1 localhostEOF
[alias1] [alias2] ...# End /etc/hosts (network card version)
need to be changed for specific uses or requirements (if assigned
an IP address by a network/system administrator and the machine
will be connected to an existing network). The optional alias
name(s) can be omitted.
If a network card is not going to be configured, create the
/etc/hosts file by running:
cat > /etc/hosts << "EOF"
# Begin /etc/hosts (no network card version) 127.0.0.1EOF
<HOSTNAME>localhost ::1 localhost # End /etc/hosts (no network card version)
The ::1 entry is the IPv6 counterpart of 127.0.0.1 and represents the IPv6 loopback interface.