systemd.network
systemd
Developer
Tom
Gundersen
teg@jklm.no
systemd.network
5
systemd.network
Network configuration
network.network
Description
Network setup is performed by
systemd-networkd8.
Network files must have the extension .network;
other extensions are ignored. Networks are applied to links whenever the links
appear.
The .network files are read from the files located in the
system network directory /usr/lib/systemd/network,
the volatile runtime network directory
/run/systemd/network and the local administration
network directory /etc/systemd/network.
All configuration files are collectively sorted and processed in lexical order,
regardless of the directories in which they live. However, files with
identical filenames replace each other. Files in
/etc have the highest priority, files in
/run take precedence over files with the same
name in /usr/lib. This can be used to override a
system-supplied configuration file with a local file if needed; a symlink in
/etc with the same name as a configuration file in
/usr/lib, pointing to /dev/null,
disables the configuration file entirely.
[Match] Section Options
The network file contains a [Match] section,
which determines if a given network file may be applied to a given device;
and a [Network] section specifying how the device should
be configured. The first (in lexical order) of the network files that
matches a given device is applied.
A network file is said to match a device if each of the entries in the
[Match] section matches, or if the section is empty.
The following keys are accepted:
MACAddress=
The hardware address.
Path=
The persistent path, as exposed by the udev
property ID_PATH. May contain shell
style globs.
Driver=
The driver currently bound to the device, as
exposed by the udev property DRIVER
of its parent device, or if that is not set the driver
as exposed by ethtool -i of the
device itself.
Type=
The device type, as exposed by the udev property
DEVTYPE.
Name=
The device name, as exposed by the udev property
INTERFACE. May contain shell style
globs.
Host=
Matches against the hostname or machine ID of the
host. See ConditionHost= in
systemd.unit5
for details.
Virtualization=
Checks whether the system is executed in a virtualized
environment and optionally test whether it is a specific
implementation. See ConditionVirtualization= in
systemd.unit5
for details.
KernelCommandLine=
Checks whether a specific kernel command line option is
set (or if prefixed with the exclamation mark unset). See
ConditionKernelCommandLine= in
systemd.unit5
for details.
Architecture=
Checks whether the system is running on a specific
architecture. See ConditionArchitecture= in
systemd.unit5
for details.
[Network] Section Options
The [Network] section accepts the following keys:
Description=
A description of the device. This is only used for
presentation purposes.
DHCP=
Enables DHCPv4 and/or DHCPv6 support. Accepts
both, none,
v4 or v6.
DHCPServer=
A boolean. Enables a basic DHCPv4 server on the
device. Mostly useful for handing out leases to container
instances.
IPv4LL=
A boolean. When true, enables IPv4 link-local support.
IPv4LLRoute=
A boolean. When true, sets up the route needed for
non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults
to false.
LLMNR=
A boolean or resolve. When true, enables
Link-Local Multicast Name Resolution on the link, when set to
resolve only resolution is enabled, but not
announcement. Defaults to true.
Address=
A static IPv4 or IPv6 address and its prefix length,
separated by a / character. Specify this
key more than once to configure several addresses.
The format of the address must be as described in
inet_pton3.
This is a short-hand for an [Address] section only containing
an Address key (see below). This option may be specified
more than once.
If the specified
address is 0.0.0.0
(for IPv4) or [::]
(for IPv6), a new
address range of the
requested size is
automatically
allocated from a
system-wide pool of
unused ranges. The
allocated range is
checked against all
current network
interfaces and all
known network
configuration files to
avoid address range
conflicts. The default
system-wide pool
consists of
192.168.0.0/16,
172.16.0.0/12 and
10.0.0.0/8 for IPv4,
and fc00::/7 for
IPv6. This
functionality is
useful to manage a
large number of
dynamically created
network interfaces
with the same network
configuration and
automatic address
range
assignment.
Gateway=
The gateway address, which must be in the format described in
inet_pton3.
This is a short-hand for a [Route] section only containing a Gateway
key. This option may be specified more than once.
DNS=
A DNS server address, which must be in the format described in
inet_pton3.
This option may be specified more than once.
Domains=
The domains used for DNS resolution over this link.
NTP=
An NTP server address. This option may be specified more than once.
Bridge=
The name of the bridge to add the link to.
Bond=
The name of the bond to add the link to.
VLAN=
The name of a VLAN to create on the link. This option
may be specified more than once.
MACVLAN=
The name of a MACVLAN to create on the link. This option
may be specified more than once.
VXLAN=
The name of a VXLAN to create on the link. This option
may be specified more than once.
Tunnel=
The name of a Tunnel to create on the link. This option
may be specified more than once.
[Address] Section Options
An [Address] section accepts the following keys.
Specify several [Address] sections to configure several
addresses.
Address=
As in the [Network] section. This key is mandatory.
Peer=
The peer address in a point-to-point connection. Accepts the same format as
the Address key.
Broadcast=
The broadcast address, which must be in the format described in
inet_pton3.
This key only applies to IPv4 addresses. If it is not given, it is
derived from the Address key.
Label=
An address label.
[Route] Section Options
The [Route] section accepts the following keys. Specify
several [Route] sections to configure several routes.
Gateway=
As in the [Network] section. This key is mandatory.
Destination=
The destination prefix of the route. Possibly followed by a slash and the
prefixlength. If omitted, a full-length host route is assumed.
Metric=
The metric of the route. An unsigned integer
[DHCP] Section Options
The [DHCP] section accepts the following keys:
UseDNS=
When true (the default), the DNS servers received from the DHCP server will
be used and take precedence over any statically configured ones.
UseMTU=
When true, the interface maximum transmission unit from the DHCP server will
be used on the current link. Defaults to false.
SendHostname=
When true (the default), the machine's hostname will be sent to the DHCP
server
UseHostname=
When true (the default), the hostname received from the DHCP server
will be used as the transient hostname.
UseDomains=
When true (not the default), the domain name received from the DHCP server
will be used for DNS resolution over this link.
UseRoutes=
When true (the default), the static routes will be requested from the DHCP server
and added to the routing table with metric of 1024.
CriticalConnection=
When true, the connection will never be torn down even if the DHCP lease
expires. This is contrary to the DHCP specification, but may be the best choice
if, say, the root filesystem relies on this connection. Defaults to false.
VendorClassIdentifier=
The vendor class identifier used to identify vendor type and configuration.
RequestBroadcast=
Request the server to use broadcast messages before the IP address has been
configured. This is necessary for devices that cannot receive RAW packets, or that
cannot receive packets at all before an IP address has been configured. On the other
hand, this must not be enabled on networks where broadcasts are filtered out.
RouteMetric=
Set the routing metric for routes specified by the DHCP server.
[BridgePort] Section Options
The [BridgePort] section accepts the following keys.
Cost=
Each port in a bridge may have different speed. Cost is used to decide which link to use. Faster interfaces should have lower costs
Example
/etc/systemd/network/50-static.network
[Match]
Name=enp2s0
[Network]
Address=192.168.0.15/24
Gateway=192.168.0.1
/etc/systemd/network/80-dhcp.network
[Match]
Name=en*
[Network]
DHCP=both
/etc/systemd/network/bridge-static.network
[Match]
Name=bridge0
[Network]
Address=192.168.0.15/24
Gateway=192.168.0.1
DNS=192.168.0.1
/etc/systemd/network/bridge-slave-interface.network
[Match]
Name=enp2s0
[Network]
Bridge=bridge0
/etc/systemd/network/ipip.network
[Match]
Name=em1
[Network]
Tunnel=ipip-tun
/etc/systemd/network/sit.network
[Match]
Name=em1
[Network]
Tunnel=sit-tun
/etc/systemd/network/gre.network
[Match]
Name=em1
[Network]
Tunnel=gre-tun
/etc/systemd/network/vti.network
[Match]
Name=em1
[Network]
Tunnel=vti-tun
See Also
systemd1,
systemd-networkd8,
systemd.netdev5