NAME¶
systemd.network - Network configuration
SYNOPSIS¶
network.network
DESCRIPTION¶
Network setup is performed by systemd-networkd(8).
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=
A whitespace-separated list of shell-style globs matching
the persistent path, as exposed by the udev property
"ID_PATH".
Driver=
A whitespace-separated list of shell-style globs matching
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=
A whitespace-separated list of shell-style globs matching
the device type, as exposed by the udev property "DEVTYPE".
Name=
A whitespace-separated list of shell-style globs matching
the device name, as exposed by the udev property "INTERFACE".
Host=
Matches against the hostname or machine ID of the host.
See "ConditionHost=" in
systemd.unit(5) 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.unit(5) 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.unit(5) for
details.
Architecture=
Checks whether the system is running on a specific
architecture. See "ConditionArchitecture=" in
systemd.unit(5)
for details.
[LINK] SECTION OPTIONS¶
The "[Link]" section accepts the following keys:
MACAddress=
The hardware address.
MTUBytes=
The maximum transmission unit in bytes to set for the
device. The usual suffixes K, M, G, are supported and are understood to the
base of 1024.
[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
"yes", "no", "ipv4", or "ipv6".
DHCPServer=
A boolean. Enables a basic DHCPv4 server on the device.
Mostly useful for handing out leases to container instances.
LinkLocalAddressing=
Enables link-local address autoconfiguration. Accepts
"yes", "no", "ipv4", or "ipv6".
Defaults to "ipv6".
IPv4LLRoute=
A boolean. When true, sets up the route needed for
non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults to
false.
IPv6Token=
An IPv6 address with the top 64 bits unset. When set,
indicates the 64 bits interface part of SLAAC IPv6 addresses for this link. By
default it is autogenerated.
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.
LLDP=
A boolean. When true, enables LLDP link receive
support.
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_pton(3). 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_pton(3). 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_pton(3). 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.
IPForward=
Configures IP forwarding for the network interface. If
enabled incoming packets on the network interface will be forwarded to other
interfaces according to the routing table. Takes either a boolean argument, or
the values "ipv4" or "ipv6", which only enables IP
forwarding for the specified address family.
IPMasquerade=
Configures IP masquerading for the network interface. If
enabled packets forwarded from the network interface will be appear as coming
from the local host. Takes a boolean argument. Implies
IPForward=yes.
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_pton(3). 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.
Destination=
The destination prefix of the route. Possibly followed by
a slash and the prefixlength. If omitted, a full-length host route is
assumed.
Source=
The source 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
Scope=
The scope of the route. One of the values
"global", "link" or "host". Defaults to
"global".
[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.
[BRIDGE] SECTION OPTIONS¶
The "[Bridge]" 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
[BRIDGEFDB] SECTION OPTIONS¶
The "[BridgeFDB]" section manages the forwarding
database table of a port and accepts the following keys. Specify several
"[BridgeFDB]" sections to configure several static MAC table
entries.
MACAddress=
As in the "[Network]" section. This key is
mandatory.
VLANId=
The VLAN Id for the new static MAC table entry. If
omitted, no VLAN Id info is appended to the new static MAC table entry.
EXAMPLE¶
Example 1. /etc/systemd/network/50-static.network
[Match]
Name=enp2s0
[Network]
Address=192.168.0.15/24
Gateway=192.168.0.1
Example 2. /etc/systemd/network/80-dhcp.network
[Match]
Name=en*
[Network]
DHCP=yes
Example 3. /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
Example 4. /etc/systemd/network/bridge-slave-interface.network
[Match]
Name=enp2s0
[Network]
Bridge=bridge0
Example 5. /etc/systemd/network/ipip.network
[Match]
Name=em1
[Network]
Tunnel=ipip-tun
Example 6. /etc/systemd/network/sit.network
[Match]
Name=em1
[Network]
Tunnel=sit-tun
Example 7. /etc/systemd/network/gre.network
[Match]
Name=em1
[Network]
Tunnel=gre-tun
Example 8. /etc/systemd/network/vti.network
[Match]
Name=em1
[Network]
Tunnel=vti-tun