SYSTEMD.NETWORK(5) systemd.network SYSTEMD.NETWORK(5)
NAME
systemd.network - Network configuration
SYNOPSIS
network.network
DESCRIPTION
A plain ini-style text file that encodes network configuration for
matching network interfaces, used by systemd-networkd(8). See
systemd.syntax(5) for a general description of the syntax.
The main network file 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 directories /lib/systemd/network and
/usr/local/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 under /usr. This can be used to override
a system-supplied configuration file with a local file if needed. As a
special case, an empty file (file size 0) or symlink with the same name
pointing to /dev/null disables the configuration file entirely (it is
"masked").
Along with the network file foo.network, a "drop-in" directory
foo.network.d/ may exist. All files with the suffix ".conf" from this
directory will be parsed after the file itself is parsed. This is
useful to alter or add configuration settings, without having to modify
the main configuration file. Each drop-in file must have appropriate
section headers.
In addition to /etc/systemd/network, drop-in ".d" directories can be
placed in /lib/systemd/network or /run/systemd/network directories.
Drop-in files in /etc take precedence over those in /run which in turn
take precedence over those in /lib. Drop-in files under any of these
directories take precedence over the main network file wherever
located.
Note that an interface without any static IPv6 addresses configured,
and neither DHCPv6 nor IPv6LL enabled, shall be considered to have no
IPv6 support. IPv6 will be automatically disabled for that interface by
writing "1" to /proc/sys/net/ipv6/conf/ifname/disable_ipv6.
[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, all later files are ignored, even if they match as well.
A network file is said to match a network interface if all matches
specified by the "[Match]" section are satisfied. When a network file
does not contain valid settings in "[Match]" section, then the file
will match all interfaces and systemd-networkd warns about that. Hint:
to avoid the warning and to make it clear that all interfaces shall be
matched, add the following:
Name=*
The following keys are accepted:
MACAddress=
A whitespace-separated list of hardware addresses. Use full colon-,
hyphen- or dot-delimited hexadecimal. See the example below. This
option may appear more than once, in which case the lists are
merged. If the empty string is assigned to this option, the list of
hardware addresses defined prior to this is reset.
Example:
MACAddress=01:23:45:67:89:ab 00-11-22-33-44-55 AABB.CCDD.EEFF
PermanentMACAddress=
A whitespace-separated list of hardware's permanent addresses.
While MACAddress= matches the device's current MAC address, this
matches the device's permanent MAC address, which may be different
from the current one. Use full colon-, hyphen- or dot-delimited
hexadecimal. This option may appear more than once, in which case
the lists are merged. If the empty string is assigned to this
option, the list of hardware addresses defined prior to this is
reset.
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 ID_NET_DRIVER of its parent device, or if that is not set,
the driver as exposed by ethtool -i of the device itself. If the
list is prefixed with a "!", the test is inverted.
Type=
A whitespace-separated list of shell-style globs matching the
device type, as exposed by networkctl status. If the list is
prefixed with a "!", the test is inverted.
Property=
A whitespace-separated list of udev property name with its value
after a equal ("="). If multiple properties are specified, the test
results are ANDed. If the list is prefixed with a "!", the test is
inverted. If a value contains white spaces, then please quote whole
key and value pair. If a value contains quotation, then please
escape the quotation with "\".
Example: if a .link file has the following:
Property=ID_MODEL_ID=9999 "ID_VENDOR_FROM_DATABASE=vendor name" "KEY=with \"quotation\""
then, the .link file matches only when an interface has all the
above three properties.
Name=
A whitespace-separated list of shell-style globs matching the
device name, as exposed by the udev property "INTERFACE", or
device's alternative names. If the list is prefixed with a "!", the
test is inverted.
WLANInterfaceType=
A whitespace-separated list of wireless network type. Supported
values are "ad-hoc", "station", "ap", "ap-vlan", "wds", "monitor",
"mesh-point", "p2p-client", "p2p-go", "p2p-device", "ocb", and
"nan". If the list is prefixed with a "!", the test is inverted.
SSID=
A whitespace-separated list of shell-style globs matching the SSID
of the currently connected wireless LAN. If the list is prefixed
with a "!", the test is inverted.
BSSID=
A whitespace-separated list of hardware address of the currently
connected wireless LAN. Use full colon-, hyphen- or dot-delimited
hexadecimal. See the example in MACAddress=. This option may appear
more than one, in which case the lists are merged. If the empty
string is assigned to this option, the list of BSSID defined prior
to this is reset.
Host=
Matches against the hostname or machine ID of the host. See
ConditionHost= in systemd.unit(5) for details. When prefixed with
an exclamation mark ("!"), the result is negated. If an empty
string is assigned, then previously assigned value is cleared.
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. When
prefixed with an exclamation mark ("!"), the result is negated. If
an empty string is assigned, then previously assigned value is
cleared.
KernelCommandLine=
Checks whether a specific kernel command line option is set. See
ConditionKernelCommandLine= in systemd.unit(5) for details. When
prefixed with an exclamation mark ("!"), the result is negated. If
an empty string is assigned, then previously assigned value is
cleared.
KernelVersion=
Checks whether the kernel version (as reported by uname -r) matches
a certain expression. See ConditionKernelVersion= in
systemd.unit(5) for details. When prefixed with an exclamation mark
("!"), the result is negated. If an empty string is assigned, then
previously assigned value is cleared.
Architecture=
Checks whether the system is running on a specific architecture.
See ConditionArchitecture= in systemd.unit(5) for details. When
prefixed with an exclamation mark ("!"), the result is negated. If
an empty string is assigned, then previously assigned value is
cleared.
[LINK] SECTION OPTIONS
The "[Link]" section accepts the following keys:
MACAddress=
The hardware address to set for the device.
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.
Note that if IPv6 is enabled on the interface, and the MTU is
chosen below 1280 (the minimum MTU for IPv6) it will automatically
be increased to this value.
ARP=
Takes a boolean. If set to true, the ARP (low-level Address
Resolution Protocol) for this interface is enabled. When unset, the
kernel's default will be used.
For example, disabling ARP is useful when creating multiple MACVLAN
or VLAN virtual interfaces atop a single lower-level physical
interface, which will then only serve as a link/"bridge" device
aggregating traffic to the same physical link and not participate
in the network otherwise.
Multicast=
Takes a boolean. If set to true, the multicast flag on the device
is enabled.
AllMulticast=
Takes a boolean. If set to true, the driver retrieves all multicast
packets from the network. This happens when multicast routing is
enabled.
Unmanaged=
Takes a boolean. When "yes", no attempts are made to bring up or
configure matching links, equivalent to when there are no matching
network files. Defaults to "no".
This is useful for preventing later matching network files from
interfering with certain interfaces that are fully controlled by
other applications.
RequiredForOnline=
Takes a boolean or a minimum operational state and an optional
maximum operational state. Please see networkctl(1) for possible
operational states. When "yes", the network is deemed required when
determining whether the system is online when running
systemd-networkd-wait-online. When "no", the network is ignored
when checking for online state. When a minimum operational state
and an optional maximum operational state are set, "yes" is
implied, and this controls the minimum and maximum operational
state required for the network interface to be considered online.
Defaults to "yes".
The network will be brought up normally in all cases, but in the
event that there is no address being assigned by DHCP or the cable
is not plugged in, the link will simply remain offline and be
skipped automatically by systemd-networkd-wait-online if
"RequiredForOnline=no".
[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 client support. Accepts "yes", "no",
"ipv4", or "ipv6". Defaults to "no".
Note that DHCPv6 will by default be triggered by Router
Advertisement, if that is enabled, regardless of this parameter. By
enabling DHCPv6 support explicitly, the DHCPv6 client will be
started regardless of the presence of routers on the link, or what
flags the routers pass. See "IPv6AcceptRA=".
Furthermore, note that by default the domain name specified through
DHCP is not used for name resolution. See option UseDomains= below.
See the "[DHCPv4]" or "[DHCPv6]" section below for further
configuration options for the DHCP client support.
DHCPServer=
Takes a boolean. If set to "yes", DHCPv4 server will be started.
Defaults to "no". Further settings for the DHCP server may be set
in the "[DHCPServer]" section described below.
LinkLocalAddressing=
Enables link-local address autoconfiguration. Accepts "yes", "no",
"ipv4", "ipv6", "fallback", or "ipv4-fallback". If "fallback" or
"ipv4-fallback" is specified, then an IPv4 link-local address is
configured only when DHCPv4 fails. If "fallback", an IPv6
link-local address is always configured, and if "ipv4-fallback",
the address is not configured. Note that, the fallback mechanism
works only when DHCPv4 client is enabled, that is, it requires
"DHCP=yes" or "DHCP=ipv4". If Bridge= is set, defaults to "no", and
if not, defaults to "ipv6".
IPv4LLRoute=
Takes a boolean. If set to true, sets up the route needed for
non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults to
false.
DefaultRouteOnDevice=
Takes a boolean. If set to true, sets up the default route bound to
the interface. Defaults to false. This is useful when creating
routes on point-to-point interfaces. This is equivalent to e.g. the
following.
ip route add default dev veth99
IPv6Token=
Specifies an optional address generation mode and a required IPv6
address. If the mode is present, the two parts must be separated
with a colon "mode:address". The address generation mode may be
either prefixstable or static. If not specified, static is assumed.
When the mode is set to static, or unspecified, the lower bits of
the supplied address are combined with the upper bits of a prefix
received in a Router Advertisement message to form a complete
address. Note that if multiple prefixes are received in an RA
message, or in multiple RA messages, addresses will be formed from
each of them using the supplied address. This mode implements SLAAC
but uses a static interface identifier instead of an identifier
generated using the EUI-64 algorithm. Because the interface
identifier is static, if Duplicate Address Detection detects that
the computed address is a duplicate (in use by another node on the
link), then this mode will fail to provide an address for that
prefix.
When the mode is set to "prefixstable" the RFC 7217 algorithm for
generating interface identifiers will be used, but only when a
prefix received in an RA message matches the supplied address. See
RFC 7217[1]. Prefix matching will be attempted against each
prefixstable IPv6Token variable provided in the configuration; if a
received prefix does not match any of the provided addresses, then
the EUI-64 algorithm will be used to form an interface identifier
for that prefix. This mode is also SLAAC, but with a potentially
stable interface identifier which does not directly map to the
interface's hardware address. Note that the prefixstable algorithm
includes both the interface's name and MAC address in the hash used
to compute the interface identifier, so if either of those are
changed the resulting interface identifier (and address) will
change, even if the prefix received in the RA message has not
changed. Note that if multiple prefixstable IPv6Token variables are
supplied with addresses that match a prefix received in an RA
message, only the first one will be used to generate addresses.
LLMNR=
Takes a boolean or "resolve". When true, enables Link-Local
Multicast Name Resolution[2] on the link. When set to "resolve",
only resolution is enabled, but not host registration and
announcement. Defaults to true. This setting is read by systemd-
resolved.service(8).
MulticastDNS=
Takes a boolean or "resolve". When true, enables Multicast DNS[3]
support on the link. When set to "resolve", only resolution is
enabled, but not host or service registration and announcement.
Defaults to false. This setting is read by systemd-
resolved.service(8).
DNSOverTLS=
Takes a boolean or "opportunistic". When true, enables
DNS-over-TLS[4] support on the link. When set to "opportunistic",
compatibility with non-DNS-over-TLS servers is increased, by
automatically turning off DNS-over-TLS servers in this case. This
option defines a per-interface setting for resolved.conf(5)'s
global DNSOverTLS= option. Defaults to false. This setting is read
by systemd-resolved.service(8).
DNSSEC=
Takes a boolean. or "allow-downgrade". When true, enables DNSSEC[5]
DNS validation support on the link. When set to "allow-downgrade",
compatibility with non-DNSSEC capable networks is increased, by
automatically turning off DNSSEC in this case. This option defines
a per-interface setting for resolved.conf(5)'s global DNSSEC=
option. Defaults to false. This setting is read by systemd-
resolved.service(8).
DNSSECNegativeTrustAnchors=
A space-separated list of DNSSEC negative trust anchor domains. If
specified and DNSSEC is enabled, look-ups done via the interface's
DNS server will be subject to the list of negative trust anchors,
and not require authentication for the specified domains, or
anything below it. Use this to disable DNSSEC authentication for
specific private domains, that cannot be proven valid using the
Internet DNS hierarchy. Defaults to the empty list. This setting is
read by systemd-resolved.service(8).
LLDP=
Controls support for Ethernet LLDP packet reception. LLDP is a
link-layer protocol commonly implemented on professional routers
and bridges which announces which physical port a system is
connected to, as well as other related data. Accepts a boolean or
the special value "routers-only". When true, incoming LLDP packets
are accepted and a database of all LLDP neighbors maintained. If
"routers-only" is set only LLDP data of various types of routers is
collected and LLDP data about other types of devices ignored (such
as stations, telephones and others). If false, LLDP reception is
disabled. Defaults to "routers-only". Use networkctl(1) to query
the collected neighbor data. LLDP is only available on Ethernet
links. See EmitLLDP= below for enabling LLDP packet emission from
the local system.
EmitLLDP=
Controls support for Ethernet LLDP packet emission. Accepts a
boolean parameter or the special values "nearest-bridge",
"non-tpmr-bridge" and "customer-bridge". Defaults to false, which
turns off LLDP packet emission. If not false, a short LLDP packet
with information about the local system is sent out in regular
intervals on the link. The LLDP packet will contain information
about the local host name, the local machine ID (as stored in
machine-id(5)) and the local interface name, as well as the pretty
hostname of the system (as set in machine-info(5)). LLDP emission
is only available on Ethernet links. Note that this setting passes
data suitable for identification of host to the network and should
thus not be enabled on untrusted networks, where such
identification data should not be made available. Use this option
to permit other systems to identify on which interfaces they are
connected to this system. The three special values control
propagation of the LLDP packets. The "nearest-bridge" setting
permits propagation only to the nearest connected bridge,
"non-tpmr-bridge" permits propagation across Two-Port MAC Relays,
but not any other bridges, and "customer-bridge" permits
propagation until a customer bridge is reached. For details about
these concepts, see IEEE 802.1AB-2016[6]. Note that configuring
this setting to true is equivalent to "nearest-bridge", the
recommended and most restricted level of propagation. See LLDP=
above for an option to enable LLDP reception.
BindCarrier=
A link name or a list of link names. When set, controls the
behavior of the current link. When all links in the list are in an
operational down state, the current link is brought down. When at
least one link has carrier, the current interface is brought up.
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. Note that the
prefix length must be equal or larger than 8 for IPv4, and 64 for
IPv6. 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 fd00::/8
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. This
setting is read by systemd-resolved.service(8).
Domains=
A whitespace-separated list of domains which should be resolved
using the DNS servers on this link. Each item in the list should be
a domain name, optionally prefixed with a tilde ("~"). The domains
with the prefix are called "routing-only domains". The domains
without the prefix are called "search domains" and are first used
as search suffixes for extending single-label host names (host
names containing no dots) to become fully qualified domain names
(FQDNs). If a single-label host name is resolved on this interface,
each of the specified search domains are appended to it in turn,
converting it into a fully qualified domain name, until one of them
may be successfully resolved.
Both "search" and "routing-only" domains are used for routing of
DNS queries: look-ups for host names ending in those domains (hence
also single label names, if any "search domains" are listed), are
routed to the DNS servers configured for this interface. The domain
routing logic is particularly useful on multi-homed hosts with DNS
servers serving particular private DNS zones on each interface.
The "routing-only" domain "~." (the tilde indicating definition of
a routing domain, the dot referring to the DNS root domain which is
the implied suffix of all valid DNS names) has special effect. It
causes all DNS traffic which does not match another configured
domain routing entry to be routed to DNS servers specified for this
interface. This setting is useful to prefer a certain set of DNS
servers if a link on which they are connected is available.
This setting is read by systemd-resolved.service(8). "Search
domains" correspond to the domain and search entries in
resolv.conf(5). Domain name routing has no equivalent in the
traditional glibc API, which has no concept of domain name servers
limited to a specific link.
DNSDefaultRoute=
Takes a boolean argument. If true, this link's configured DNS
servers are used for resolving domain names that do not match any
link's configured Domains= setting. If false, this link's
configured DNS servers are never used for such domains, and are
exclusively used for resolving names that match at least one of the
domains configured on this link. If not specified defaults to an
automatic mode: queries not matching any link's configured domains
will be routed to this link if it has no routing-only domains
configured.
NTP=
An NTP server address. This option may be specified more than once.
This setting is read by systemd-timesyncd.service(8).
IPForward=
Configures IP packet forwarding for the system. If enabled,
incoming packets on any network interface will be forwarded to any
other interfaces according to the routing table. Takes a boolean,
or the values "ipv4" or "ipv6", which only enable IP packet
forwarding for the specified address family. This controls the
net.ipv4.ip_forward and net.ipv6.conf.all.forwarding sysctl options
of the network interface (see ip-sysctl.txt[7] for details about
sysctl options). Defaults to "no".
Note: this setting controls a global kernel option, and does so one
way only: if a network that has this setting enabled is set up the
global setting is turned on. However, it is never turned off again,
even after all networks with this setting enabled are shut down
again.
To allow IP packet forwarding only between specific network
interfaces use a firewall.
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=ipv4. Defaults to "no".
IPv6PrivacyExtensions=
Configures use of stateless temporary addresses that change over
time (see RFC 4941[8], Privacy Extensions for Stateless Address
Autoconfiguration in IPv6). Takes a boolean or the special values
"prefer-public" and "kernel". When true, enables the privacy
extensions and prefers temporary addresses over public addresses.
When "prefer-public", enables the privacy extensions, but prefers
public addresses over temporary addresses. When false, the privacy
extensions remain disabled. When "kernel", the kernel's default
setting will be left in place. Defaults to "no".
IPv6AcceptRA=
Takes a boolean. Controls IPv6 Router Advertisement (RA) reception
support for the interface. If true, RAs are accepted; if false, RAs
are ignored. When RAs are accepted, they may trigger the start of
the DHCPv6 client if the relevant flags are set in the RA data, or
if no routers are found on the link. The default is to disable RA
reception for bridge devices or when IP forwarding is enabled, and
to enable it otherwise. Cannot be enabled on bond devices and when
link local adressing is disabled.
Further settings for the IPv6 RA support may be configured in the
"[IPv6AcceptRA]" section, see below.
Also see ip-sysctl.txt[7] in the kernel documentation regarding
"accept_ra", but note that systemd's setting of 1 (i.e. true)
corresponds to kernel's setting of 2.
Note that kernel's implementation of the IPv6 RA protocol is always
disabled, regardless of this setting. If this option is enabled, a
userspace implementation of the IPv6 RA protocol is used, and the
kernel's own implementation remains disabled, since
systemd-networkd needs to know all details supplied in the
advertisements, and these are not available from the kernel if the
kernel's own implementation is used.
IPv6DuplicateAddressDetection=
Configures the amount of IPv6 Duplicate Address Detection (DAD)
probes to send. When unset, the kernel's default will be used.
IPv6HopLimit=
Configures IPv6 Hop Limit. For each router that forwards the
packet, the hop limit is decremented by 1. When the hop limit field
reaches zero, the packet is discarded. When unset, the kernel's
default will be used.
IPv4ProxyARP=
Takes a boolean. Configures proxy ARP for IPv4. Proxy ARP is the
technique in which one host, usually a router, answers ARP requests
intended for another machine. By "faking" its identity, the router
accepts responsibility for routing packets to the "real"
destination. (see RFC 1027[9]. When unset, the kernel's default
will be used.
IPv6ProxyNDP=
Takes a boolean. Configures proxy NDP for IPv6. Proxy NDP (Neighbor
Discovery Protocol) is a technique for IPv6 to allow routing of
addresses to a different destination when peers expect them to be
present on a certain physical link. In this case a router answers
Neighbour Advertisement messages intended for another machine by
offering its own MAC address as destination. Unlike proxy ARP for
IPv4, it is not enabled globally, but will only send Neighbour
Advertisement messages for addresses in the IPv6 neighbor proxy
table, which can also be shown by ip -6 neighbour show proxy.
systemd-networkd will control the per-interface `proxy_ndp` switch
for each configured interface depending on this option. When unset,
the kernel's default will be used.
IPv6ProxyNDPAddress=
An IPv6 address, for which Neighbour Advertisement messages will be
proxied. This option may be specified more than once.
systemd-networkd will add the IPv6ProxyNDPAddress= entries to the
kernel's IPv6 neighbor proxy table. This option implies
IPv6ProxyNDP=yes but has no effect if IPv6ProxyNDP has been set to
false. When unset, the kernel's default will be used.
IPv6PrefixDelegation=
Whether to enable or disable Router Advertisement sending on a
link. Allowed values are "static" which distributes prefixes as
defined in the "[IPv6PrefixDelegation]" and any "[IPv6Prefix]"
sections, "dhcpv6" which requests prefixes using a DHCPv6 client
configured for another link and any values configured in the
"[IPv6PrefixDelegation]" section while ignoring all static prefix
configuration sections, "yes" which uses both static configuration
and DHCPv6, and "false" which turns off IPv6 prefix delegation
altogether. Defaults to "false". See the "[IPv6PrefixDelegation]"
and the "[IPv6Prefix]" sections for more configuration options.
IPv6MTUBytes=
Configures IPv6 maximum transmission unit (MTU). An integer greater
than or equal to 1280 bytes. When unset, the kernel's default will
be used.
Bridge=
The name of the bridge to add the link to. See systemd.netdev(5).
Bond=
The name of the bond to add the link to. See systemd.netdev(5).
VRF=
The name of the VRF to add the link to. See systemd.netdev(5).
VLAN=
The name of a VLAN to create on the link. See systemd.netdev(5).
This option may be specified more than once.
IPVLAN=
The name of a IPVLAN to create on the link. See systemd.netdev(5).
This option may be specified more than once.
MACVLAN=
The name of a MACVLAN to create on the link. See systemd.netdev(5).
This option may be specified more than once.
VXLAN=
The name of a VXLAN to create on the link. See systemd.netdev(5).
This option may be specified more than once.
Tunnel=
The name of a Tunnel to create on the link. See systemd.netdev(5).
This option may be specified more than once.
MACsec=
The name of a MACsec device to create on the link. See
systemd.netdev(5). This option may be specified more than once.
ActiveSlave=
Takes a boolean. Specifies the new active slave. The "ActiveSlave="
option is only valid for following modes: "active-backup",
"balance-alb" and "balance-tlb". Defaults to false.
PrimarySlave=
Takes a boolean. Specifies which slave is the primary device. The
specified device will always be the active slave while it is
available. Only when the primary is off-line will alternate devices
be used. This is useful when one slave is preferred over another,
e.g. when one slave has higher throughput than another. The
"PrimarySlave=" option is only valid for following modes:
"active-backup", "balance-alb" and "balance-tlb". Defaults to
false.
ConfigureWithoutCarrier=
Takes a boolean. Allows networkd to configure a specific link even
if it has no carrier. Defaults to false.
IgnoreCarrierLoss=
A boolean. Allows networkd to retain both the static and dynamic
configuration of the interface even if its carrier is lost.
Defaults to false.
Xfrm=
The name of the xfrm to create on the link. See systemd.netdev(5).
This option may be specified more than once.
KeepConfiguration=
Takes a boolean or one of "static", "dhcp-on-stop", "dhcp". When
"static", systemd-networkd will not drop static addresses and
routes on starting up process. When set to "dhcp-on-stop",
systemd-networkd will not drop addresses and routes on stopping the
daemon. When "dhcp", the addresses and routes provided by a DHCP
server will never be dropped even if the DHCP lease expires. This
is contrary to the DHCP specification, but may be the best choice
if, e.g., the root filesystem relies on this connection. The
setting "dhcp" implies "dhcp-on-stop", and "yes" implies "dhcp" and
"static". Defaults to "no".
[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. Each
"[Address]" section can contain one Address= setting.
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.
PreferredLifetime=
Allows the default "preferred lifetime" of the address to be
overridden. Only three settings are accepted: "forever" or
"infinity" which is the default and means that the address never
expires, and "0" which means that the address is considered
immediately "expired" and will not be used, unless explicitly
requested. A setting of PreferredLifetime=0 is useful for addresses
which are added to be used only by a specific application, which is
then configured to use them explicitly.
Scope=
The scope of the address, which can be "global", "link" or "host"
or an unsigned integer ranges 0 to 255. Defaults to "global".
HomeAddress=
Takes a boolean. Designates this address the "home address" as
defined in RFC 6275[10]. Supported only on IPv6. Defaults to false.
DuplicateAddressDetection=
Takes one of "ipv4", "ipv6", "both", "none". When "ipv4", performs
IPv4 Duplicate Address Detection. See RFC 5224[11]. When "ipv6",
performs IPv6 Duplicate Address Detection. See RFC 4862[12].
Defaults to "ipv6".
ManageTemporaryAddress=
Takes a boolean. If true the kernel manage temporary addresses
created from this one as template on behalf of Privacy Extensions
RFC 3041[13]. For this to become active, the use_tempaddr sysctl
setting has to be set to a value greater than zero. The given
address needs to have a prefix length of 64. This flag allows using
privacy extensions in a manually configured network, just like if
stateless auto-configuration was active. Defaults to false.
AddPrefixRoute=
Takes a boolean. When true, the prefix route for the address is
automatically added. Defaults to true.
AutoJoin=
Takes a boolean. Joining multicast group on ethernet level via ip
maddr command would not work if we have an Ethernet switch that
does IGMP snooping since the switch would not replicate multicast
packets on ports that did not have IGMP reports for the multicast
addresses. Linux vxlan interfaces created via ip link add vxlan or
networkd's netdev kind vxlan have the group option that enables
then to do the required join. By extending ip address command with
option "autojoin" we can get similar functionality for openvswitch
(OVS) vxlan interfaces as well as other tunneling mechanisms that
need to receive multicast traffic. Defaults to "no".
[NEIGHBOR] SECTION OPTIONS
A "[Neighbor]" section accepts the following keys. The neighbor section
adds a permanent, static entry to the neighbor table (IPv6) or ARP
table (IPv4) for the given hardware address on the links matched for
the network. Specify several "[Neighbor]" sections to configure several
static neighbors.
Address=
The IP address of the neighbor.
LinkLayerAddress=
The link layer address (MAC address or IP address) of the neighbor.
[IPV6ADDRESSLABEL] SECTION OPTIONS
An "[IPv6AddressLabel]" section accepts the following keys. Specify
several "[IPv6AddressLabel]" sections to configure several address
labels. IPv6 address labels are used for address selection. See RFC
3484[14]. Precedence is managed by userspace, and only the label itself
is stored in the kernel
Label=
The label for the prefix (an unsigned integer) ranges 0 to
4294967294. 0xffffffff is reserved. This key is mandatory.
Prefix=
IPv6 prefix is an address with a prefix length, separated by a
slash "/" character. This key is mandatory.
[ROUTINGPOLICYRULE] SECTION OPTIONS
An "[RoutingPolicyRule]" section accepts the following keys. Specify
several "[RoutingPolicyRule]" sections to configure several rules.
TypeOfService=
Specifies the type of service to match a number between 0 to 255.
From=
Specifies the source address prefix to match. Possibly followed by
a slash and the prefix length.
To=
Specifies the destination address prefix to match. Possibly
followed by a slash and the prefix length.
FirewallMark=
Specifies the iptables firewall mark value to match (a number
between 1 and 4294967295).
Table=
Specifies the routing table identifier to lookup if the rule
selector matches. Takes one of "default", "main", and "local", or a
number between 1 and 4294967295. Defaults to "main".
Priority=
Specifies the priority of this rule. Priority= is an unsigned
integer. Higher number means lower priority, and rules get
processed in order of increasing number.
IncomingInterface=
Specifies incoming device to match. If the interface is loopback,
the rule only matches packets originating from this host.
OutgoingInterface=
Specifies the outgoing device to match. The outgoing interface is
only available for packets originating from local sockets that are
bound to a device.
SourcePort=
Specifies the source IP port or IP port range match in forwarding
information base (FIB) rules. A port range is specified by the
lower and upper port separated by a dash. Defaults to unset.
DestinationPort=
Specifies the destination IP port or IP port range match in
forwarding information base (FIB) rules. A port range is specified
by the lower and upper port separated by a dash. Defaults to unset.
IPProtocol=
Specifies the IP protocol to match in forwarding information base
(FIB) rules. Takes IP protocol name such as "tcp", "udp" or "sctp",
or IP protocol number such as "6" for "tcp" or "17" for "udp".
Defaults to unset.
InvertRule=
A boolean. Specifies whether the rule is to be inverted. Defaults
to false.
Family=
Takes a special value "ipv4", "ipv6", or "both". By default, the
address family is determined by the address specified in To= or
From=. If neither To= nor From= are specified, then defaults to
"ipv4".
User=
Takes a username, a user ID, or a range of user IDs separated by a
dash. Defaults to unset.
SuppressPrefixLength=
Takes a number N in the range 0-128 and rejects routing decisions
that have a prefix length of N or less. Defaults to unset.
[NEXTHOP] SECTION OPTIONS
The "[NextHop]" section accepts the following keys. Specify several
"[NextHop]" sections to configure several nexthop. Nexthop is used to
manipulate entries in the kernel's nexthop tables.
Gateway=
As in the "[Network]" section. This is mandatory.
Id=
The id of the nexthop (an unsigned integer). If unspecified or '0'
then automatically chosen by kernel.
[ROUTE] SECTION OPTIONS
The "[Route]" section accepts the following keys. Specify several
"[Route]" sections to configure several routes.
Gateway=
Takes the gateway address or special value "_dhcp". If "_dhcp",
then the gateway address provided by DHCP (or in the IPv6 case,
provided by IPv6 RA) is used.
GatewayOnLink=
Takes a boolean. If set to true, the kernel does not have to check
if the gateway is reachable directly by the current machine (i.e.,
the kernel does not need to check if the gateway is attached to the
local network), so that we can insert the route in the kernel table
without it being complained about. Defaults to "no".
Destination=
The destination prefix of the route. Possibly followed by a slash
and the prefix length. If omitted, a full-length host route is
assumed.
Source=
The source prefix of the route. Possibly followed by a slash and
the prefix length. If omitted, a full-length host route is assumed.
Metric=
The metric of the route (an unsigned integer).
IPv6Preference=
Specifies the route preference as defined in RFC4191[15] for Router
Discovery messages. Which can be one of "low" the route has a
lowest priority, "medium" the route has a default priority or
"high" the route has a highest priority.
Scope=
The scope of the route, which can be "global", "site", "link",
"host", or "nowhere". For IPv4 route, defaults to "host" if Type=
is "local" or "nat", and "link" if Type= is "broadcast",
"multicast", or "anycast". In other cases, defaults to "global".
PreferredSource=
The preferred source address of the route. The address must be in
the format described in inet_pton(3).
Table=
The table identifier for the route. Takes "default", "main",
"local" or a number between 1 and 4294967295. The table can be
retrieved using ip route show table num. If unset and Type= is
"local", "broadcast", "anycast", or "nat", then "local" is used. In
other cases, defaults to "main".
Protocol=
The protocol identifier for the route. Takes a number between 0 and
255 or the special values "kernel", "boot", "static", "ra" and
"dhcp". Defaults to "static".
Type=
Specifies the type for the route. Takes one of "unicast", "local",
"broadcast", "anycast", "multicast", "blackhole", "unreachable",
"prohibit", "throw", "nat", and "xresolve". If "unicast", a regular
route is defined, i.e. a route indicating the path to take to a
destination network address. If "blackhole", packets to the defined
route are discarded silently. If "unreachable", packets to the
defined route are discarded and the ICMP message "Host Unreachable"
is generated. If "prohibit", packets to the defined route are
discarded and the ICMP message "Communication Administratively
Prohibited" is generated. If "throw", route lookup in the current
routing table will fail and the route selection process will return
to Routing Policy Database (RPDB). Defaults to "unicast".
InitialCongestionWindow=
The TCP initial congestion window is used during the start of a TCP
connection. During the start of a TCP session, when a client
requests a resource, the server's initial congestion window
determines how many data bytes will be sent during the initial
burst of data. Takes a size in bytes between 1 and 4294967295 (2^32
- 1). The usual suffixes K, M, G are supported and are understood
to the base of 1024. When unset, the kernel's default will be used.
InitialAdvertisedReceiveWindow=
The TCP initial advertised receive window is the amount of receive
data (in bytes) that can initially be buffered at one time on a
connection. The sending host can send only that amount of data
before waiting for an acknowledgment and window update from the
receiving host. Takes a size in bytes between 1 and 4294967295
(2^32 - 1). The usual suffixes K, M, G are supported and are
understood to the base of 1024. When unset, the kernel's default
will be used.
QuickAck=
Takes a boolean. When true enables TCP quick ack mode for the
route. When unset, the kernel's default will be used.
FastOpenNoCookie=
Takes a boolean. When true enables TCP fastopen without a cookie on
a per-route basis. When unset, the kernel's default will be used.
TTLPropagate=
Takes a boolean. When true enables TTL propagation at Label
Switched Path (LSP) egress. When unset, the kernel's default will
be used.
MTUBytes=
The maximum transmission unit in bytes to set for the route. The
usual suffixes K, M, G, are supported and are understood to the
base of 1024.
Note that if IPv6 is enabled on the interface, and the MTU is
chosen below 1280 (the minimum MTU for IPv6) it will automatically
be increased to this value.
IPServiceType=
Takes string; "CS6" or "CS4". Used to set IP service type to CS6
(network control) or CS4 (Realtime). Defaults to CS6.
MultiPathRoute=address[@name] [weight]
Configures multipath route. Multipath routing is the technique of
using multiple alternative paths through a network. Takes gateway
address. Optionally, takes a network interface name or index
separated with "@", and a weight in 1..256 for this multipath route
separated with whitespace. This setting can be specified multiple
times. If an empty string is assigned, then the all previous
assignments are cleared.
[DHCPV4] SECTION OPTIONS
The "[DHCPv4]" section configures the DHCPv4 client, if it is enabled
with the DHCP= setting described above:
UseDNS=
When true (the default), the DNS servers received from the DHCP
server will be used and take precedence over any statically
configured ones.
This corresponds to the nameserver option in resolv.conf(5).
RoutesToDNS=
When true, the routes to the DNS servers received from the DHCP
server will be configured. When UseDNS= is disabled, this setting
is ignored. Defaults to false.
UseNTP=
When true (the default), the NTP servers received from the DHCP
server will be used by systemd-timesyncd and take precedence over
any statically configured ones.
UseSIP=
When true (the default), the SIP servers received from the DHCP
server will be saved at the state files and can be read via
sd_network_link_get_sip_servers() function.
UseMTU=
When true, the interface maximum transmission unit from the DHCP
server will be used on the current link. If MTUBytes= is set, then
this setting is ignored. Defaults to false.
Anonymize=
Takes a boolean. When true, the options sent to the DHCP server
will follow the RFC 7844[16] (Anonymity Profiles for DHCP Clients)
to minimize disclosure of identifying information. Defaults to
false.
This option should only be set to true when MACAddressPolicy= is
set to "random" (see systemd.link(5)).
Note that this configuration will overwrite others. In concrete,
the following variables will be ignored: SendHostname=,
ClientIdentifier=, UseRoutes=, UseMTU=, VendorClassIdentifier=,
UseTimezone=.
With this option enabled DHCP requests will mimic those generated
by Microsoft Windows, in order to reduce the ability to fingerprint
and recognize installations. This means DHCP request sizes will
grow and lease data will be more comprehensive than normally,
though most of the requested data is not actually used.
SendHostname=
When true (the default), the machine's hostname will be sent to the
DHCP server. Note that the machine's hostname must consist only of
7-bit ASCII lower-case characters and no spaces or dots, and be
formatted as a valid DNS domain name. Otherwise, the hostname is
not sent even if this is set to true.
UseHostname=
When true (the default), the hostname received from the DHCP server
will be set as the transient hostname of the system.
Hostname=
Use this value for the hostname which is sent to the DHCP server,
instead of machine's hostname. Note that the specified hostname
must consist only of 7-bit ASCII lower-case characters and no
spaces or dots, and be formatted as a valid DNS domain name.
UseDomains=
Takes a boolean, or the special value "route". When true, the
domain name received from the DHCP server will be used as DNS
search domain over this link, similar to the effect of the Domains=
setting. If set to "route", the domain name received from the DHCP
server will be used for routing DNS queries only, but not for
searching, similar to the effect of the Domains= setting when the
argument is prefixed with "~". Defaults to false.
It is recommended to enable this option only on trusted networks,
as setting this affects resolution of all host names, in particular
of single-label names. It is generally safer to use the supplied
domain only as routing domain, rather than as search domain, in
order to not have it affect local resolution of single-label names.
When set to true, this setting corresponds to the domain option in
resolv.conf(5).
UseRoutes=
When true (the default), the static routes will be requested from
the DHCP server and added to the routing table with a metric of
1024, and a scope of "global", "link" or "host", depending on the
route's destination and gateway. If the destination is on the local
host, e.g., 127.x.x.x, or the same as the link's own address, the
scope will be set to "host". Otherwise if the gateway is null (a
direct route), a "link" scope will be used. For anything else,
scope defaults to "global".
UseGateway=
When true, the gateway will be requested from the DHCP server and
added to the routing table with a metric of 1024, and a scope of
"link". When unset, the value specified with UseRoutes= is used.
UseTimezone=
When true, the timezone received from the DHCP server will be set
as timezone of the local system. Defaults to "no".
ClientIdentifier=
The DHCPv4 client identifier to use. Takes one of "mac", "duid" or
"duid-only". If set to "mac", the MAC address of the link is used.
If set to "duid", an RFC4361-compliant Client ID, which is the
combination of IAID and DUID (see below), is used. If set to
"duid-only", only DUID is used, this may not be RFC compliant, but
some setups may require to use this. Defaults to "duid".
VendorClassIdentifier=
The vendor class identifier used to identify vendor type and
configuration.
UserClass=
A DHCPv4 client can use UserClass option to identify the type or
category of user or applications it represents. The information
contained in this option is a string that represents the user class
of which the client is a member. Each class sets an identifying
string of information to be used by the DHCP service to classify
clients. Takes a whitespace-separated list of strings.
MaxAttempts=
Specifies how many times the DHCPv4 client configuration should be
attempted. Takes a number or "infinity". Defaults to "infinity".
Note that the time between retries is increased exponentially, so
the network will not be overloaded even if this number is high.
DUIDType=
Override the global DUIDType setting for this network. See
networkd.conf(5) for a description of possible values.
DUIDRawData=
Override the global DUIDRawData setting for this network. See
networkd.conf(5) for a description of possible values.
IAID=
The DHCP Identity Association Identifier (IAID) for the interface,
a 32-bit unsigned integer.
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.
RouteTable=num
The table identifier for DHCP routes (a number between 1 and
4294967295, or 0 to unset). The table can be retrieved using ip
route show table num.
When used in combination with VRF= the VRF's routing table is used
unless this parameter is specified.
RouteMTUBytes=
Specifies the MTU for the DHCP routes. Please see the [Route]
section for further details.
ListenPort=
Allow setting custom port for the DHCP client to listen on.
SendRelease=
When true, the DHCPv4 client sends a DHCP release packet when it
stops. Defaults to true.
SendDecline=
A boolen. When "true", DHCPv4 clients receives IP address from DHCP
server. After new IP is received, DHCPv4 performs IPv4 Duplicate
Address Detection. If duplicate use of IP is detected the DHCPv4
client rejects the IP by sending a DHCPDECLINE packet DHCP clients
try to obtain an IP address again. See RFC 5224[11]. Defaults to
"unset".
BlackList=
A whitespace-separated list of IPv4 addresses. DHCP offers from
servers in the list are rejected.
RequestOptions=
A whitespace-separated list of integers in the range 1-254.
SendOption=
Send an arbitrary option in the DHCPv4 request. Takes a DHCP option
number, data type and data separated with a colon
("option:type:value"). The option number must be an integer in the
range 1..254. The type takes one of "uint8", "uint16", "uint32",
"ipv4address", or "string". Special characters in the data string
may be escaped using C-style escapes[17]. This setting can be
specified multiple times. If an empty string is specified, then all
options specified earlier are cleared. Defaults to unset.
[DHCPV6] SECTION OPTIONS
The "[DHCPv6]" section configures the DHCPv6 client, if it is enabled
with the DHCP= setting described above, or invoked by the IPv6 Router
Advertisement:
UseDNS=, UseNTP=
As in the "[DHCPv4]" section.
RapidCommit=
Takes a boolean. The DHCPv6 client can obtain configuration
parameters from a DHCPv6 server through a rapid two-message
exchange (solicit and reply). When the rapid commit option is
enabled by both the DHCPv6 client and the DHCPv6 server, the
two-message exchange is used, rather than the default four-method
exchange (solicit, advertise, request, and reply). The two-message
exchange provides faster client configuration and is beneficial in
environments in which networks are under a heavy load. See RFC
3315[18] for details. Defaults to true.
ForceDHCPv6PDOtherInformation=
Takes a boolean that enforces DHCPv6 stateful mode when the 'Other
information' bit is set in Router Advertisement messages. By
default setting only the 'O' bit in Router Advertisements makes
DHCPv6 request network information in a stateless manner using a
two-message Information Request and Information Reply message
exchange. RFC 7084[19], requirement WPD-4, updates this behavior
for a Customer Edge router so that stateful DHCPv6 Prefix
Delegation is also requested when only the 'O' bit is set in Router
Advertisements. This option enables such a CE behavior as it is
impossible to automatically distinguish the intention of the 'O'
bit otherwise. By default this option is set to 'false', enable it
if no prefixes are delegated when the device should be acting as a
CE router.
PrefixDelegationHint=
Takes an IPv6 address with prefix length as Address= in the
"[Network]" section. Specifies the DHCPv6 client for the requesting
router to include a prefix-hint in the DHCPv6 solicitation. Prefix
ranges 1-128. Defaults to unset.
[IPV6ACCEPTRA] SECTION OPTIONS
The "[IPv6AcceptRA]" section configures the IPv6 Router Advertisement
(RA) client, if it is enabled with the IPv6AcceptRA= setting described
above:
UseDNS=
When true (the default), the DNS servers received in the Router
Advertisement will be used and take precedence over any statically
configured ones.
This corresponds to the nameserver option in resolv.conf(5).
UseDomains=
Takes a boolean, or the special value "route". When true, the
domain name received via IPv6 Router Advertisement (RA) will be
used as DNS search domain over this link, similar to the effect of
the Domains= setting. If set to "route", the domain name received
via IPv6 RA will be used for routing DNS queries only, but not for
searching, similar to the effect of the Domains= setting when the
argument is prefixed with "~". Defaults to false.
It is recommended to enable this option only on trusted networks,
as setting this affects resolution of all host names, in particular
of single-label names. It is generally safer to use the supplied
domain only as routing domain, rather than as search domain, in
order to not have it affect local resolution of single-label names.
When set to true, this setting corresponds to the domain option in
resolv.conf(5).
RouteTable=num
The table identifier for the routes received in the Router
Advertisement (a number between 1 and 4294967295, or 0 to unset).
The table can be retrieved using ip route show table num.
UseAutonomousPrefix=
When true (the default), the autonomous prefix received in the
Router Advertisement will be used and take precedence over any
statically configured ones.
UseOnLinkPrefix=
When true (the default), the onlink prefix received in the Router
Advertisement will be used and take precedence over any statically
configured ones.
BlackList=
A whitespace-separated list of IPv6 prefixes. IPv6 prefixes
supplied via router advertisements in the list are ignored.
[DHCPSERVER] SECTION OPTIONS
The "[DHCPServer]" section contains settings for the DHCP server, if
enabled via the DHCPServer= option described above:
PoolOffset=, PoolSize=
Configures the pool of addresses to hand out. The pool is a
contiguous sequence of IP addresses in the subnet configured for
the server address, which does not include the subnet nor the
broadcast address. PoolOffset= takes the offset of the pool from
the start of subnet, or zero to use the default value. PoolSize=
takes the number of IP addresses in the pool or zero to use the
default value. By default, the pool starts at the first address
after the subnet address and takes up the rest of the subnet,
excluding the broadcast address. If the pool includes the server
address (the default), this is reserved and not handed out to
clients.
DefaultLeaseTimeSec=, MaxLeaseTimeSec=
Control the default and maximum DHCP lease time to pass to clients.
These settings take time values in seconds or another common time
unit, depending on the suffix. The default lease time is used for
clients that did not ask for a specific lease time. If a client
asks for a lease time longer than the maximum lease time, it is
automatically shortened to the specified time. The default lease
time defaults to 1h, the maximum lease time to 12h. Shorter lease
times are beneficial if the configuration data in DHCP leases
changes frequently and clients shall learn the new settings with
shorter latencies. Longer lease times reduce the generated DHCP
network traffic.
EmitDNS=, DNS=
Takes a boolean. Configures whether the DHCP leases handed out to
clients shall contain DNS server information. Defaults to "yes".
The DNS servers to pass to clients may be configured with the DNS=
option, which takes a list of IPv4 addresses. If the EmitDNS=
option is enabled but no servers configured, the servers are
automatically propagated from an "uplink" interface that has
appropriate servers set. The "uplink" interface is determined by
the default route of the system with the highest priority. Note
that this information is acquired at the time the lease is handed
out, and does not take uplink interfaces into account that acquire
DNS or NTP server information at a later point. DNS server
propagation does not take /etc/resolv.conf into account. Also, note
that the leases are not refreshed if the uplink network
configuration changes. To ensure clients regularly acquire the most
current uplink DNS server information, it is thus advisable to
shorten the DHCP lease time via MaxLeaseTimeSec= described above.
EmitNTP=, NTP=
Similar to the EmitDNS= and DNS= settings described above, these
settings configure whether and what NTP server information shall be
emitted as part of the DHCP lease. The same syntax, propagation
semantics and defaults apply as for EmitDNS= and DNS=.
EmitSIP=, SIP=
Similar to the EmitDNS= and DNS= settings described above, these
settings configure whether and what SIP server information shall be
emitted as part of the DHCP lease. The same syntax, propagation
semantics and defaults apply as for EmitDNS= and DNS=.
EmitRouter=
Similar to the EmitDNS= setting described above, this setting
configures whether the DHCP lease should contain the router option.
The same syntax, propagation semantics and defaults apply as for
EmitDNS=.
EmitTimezone=, Timezone=
Takes a boolean. Configures whether the DHCP leases handed out to
clients shall contain timezone information. Defaults to "yes". The
Timezone= setting takes a timezone string (such as "Europe/Berlin"
or "UTC") to pass to clients. If no explicit timezone is set, the
system timezone of the local host is propagated, as determined by
the /etc/localtime symlink.
SendOption=
Send a raw option with value via DHCPv4 server. Takes a DHCP option
number, data type and data ("option:type:value"). The option number
is an integer in the range 1..254. The type takes one of "uint8",
"uint16", "uint32", "ipv4address", or "string". Special characters
in the data string may be escaped using C-style escapes[17]. This
setting can be specified multiple times. If an empty string is
specified, then all options specified earlier are cleared. Defaults
to unset.
[IPV6PREFIXDELEGATION] SECTION OPTIONS
The "[IPv6PrefixDelegation]" section contains settings for sending IPv6
Router Advertisements and whether to act as a router, if enabled via
the IPv6PrefixDelegation= option described above. IPv6 network prefixes
are defined with one or more "[IPv6Prefix]" sections.
Managed=, OtherInformation=
Takes a boolean. Controls whether a DHCPv6 server is used to
acquire IPv6 addresses on the network link when Managed= is set to
"true" or if only additional network information can be obtained
via DHCPv6 for the network link when OtherInformation= is set to
"true". Both settings default to "false", which means that a DHCPv6
server is not being used.
RouterLifetimeSec=
Takes a timespan. Configures the IPv6 router lifetime in seconds.
If set, this host also announces itself in Router Advertisements as
an IPv6 router for the network link. When unset, the host is not
acting as a router.
RouterPreference=
Configures IPv6 router preference if RouterLifetimeSec= is
non-zero. Valid values are "high", "medium" and "low", with
"normal" and "default" added as synonyms for "medium" just to make
configuration easier. See RFC 4191[15] for details. Defaults to
"medium".
EmitDNS=, DNS=
DNS= specifies a list of recursive DNS server IPv6 addresses that
are distributed via Router Advertisement messages when EmitDNS= is
true. DNS= also takes special value "_link_local"; in that case
the IPv6 link local address is distributed. If DNS= is empty, DNS
servers are read from the "[Network]" section. If the "[Network]"
section does not contain any DNS servers either, DNS servers from
the uplink with the highest priority default route are used. When
EmitDNS= is false, no DNS server information is sent in Router
Advertisement messages. EmitDNS= defaults to true.
EmitDomains=, Domains=
A list of DNS search domains distributed via Router Advertisement
messages when EmitDomains= is true. If Domains= is empty, DNS
search domains are read from the "[Network]" section. If the
"[Network]" section does not contain any DNS search domains either,
DNS search domains from the uplink with the highest priority
default route are used. When EmitDomains= is false, no DNS search
domain information is sent in Router Advertisement messages.
EmitDomains= defaults to true.
DNSLifetimeSec=
Lifetime in seconds for the DNS server addresses listed in DNS= and
search domains listed in Domains=.
[IPV6PREFIX] SECTION OPTIONS
One or more "[IPv6Prefix]" sections contain the IPv6 prefixes that are
announced via Router Advertisements. See RFC 4861[20] for further
details.
AddressAutoconfiguration=, OnLink=
Takes a boolean to specify whether IPv6 addresses can be
autoconfigured with this prefix and whether the prefix can be used
for onlink determination. Both settings default to "true" in order
to ease configuration.
Prefix=
The IPv6 prefix that is to be distributed to hosts. Similarly to
configuring static IPv6 addresses, the setting is configured as an
IPv6 prefix and its prefix length, separated by a "/" character.
Use multiple "[IPv6Prefix]" sections to configure multiple IPv6
prefixes since prefix lifetimes, address autoconfiguration and
onlink status may differ from one prefix to another.
PreferredLifetimeSec=, ValidLifetimeSec=
Preferred and valid lifetimes for the prefix measured in seconds.
PreferredLifetimeSec= defaults to 604800 seconds (one week) and
ValidLifetimeSec= defaults to 2592000 seconds (30 days).
[IPV6ROUTEPREFIX] SECTION OPTIONS
One or more "[IPv6RoutePrefix]" sections contain the IPv6 prefix routes
that are announced via Router Advertisements. See RFC 4191[15] for
further details.
Route=
The IPv6 route that is to be distributed to hosts. Similarly to
configuring static IPv6 routes, the setting is configured as an
IPv6 prefix routes and its prefix route length, separated by a"/"
character. Use multiple "[IPv6PrefixRoutes]" sections to configure
multiple IPv6 prefix routes.
LifetimeSec=
Lifetime for the route prefix measured in seconds. LifetimeSec=
defaults to 604800 seconds (one week).
[BRIDGE] SECTION OPTIONS
The "[Bridge]" section accepts the following keys.
UnicastFlood=
Takes a boolean. Controls whether the bridge should flood traffic
for which an FDB entry is missing and the destination is unknown
through this port. When unset, the kernel's default will be used.
MulticastFlood=
Takes a boolean. Controls whether the bridge should flood traffic
for which an MDB entry is missing and the destination is unknown
through this port. When unset, the kernel's default will be used.
MulticastToUnicast=
Takes a boolean. Multicast to unicast works on top of the multicast
snooping feature of the bridge. Which means unicast copies are only
delivered to hosts which are interested in it. When unset, the
kernel's default will be used.
NeighborSuppression=
Takes a boolean. Configures whether ARP and ND neighbor suppression
is enabled for this port. When unset, the kernel's default will be
used.
Learning=
Takes a boolean. Configures whether MAC address learning is enabled
for this port. When unset, the kernel's default will be used.
HairPin=
Takes a boolean. Configures whether traffic may be sent back out of
the port on which it was received. When this flag is false, and the
bridge will not forward traffic back out of the receiving port.
When unset, the kernel's default will be used.
UseBPDU=
Takes a boolean. Configures whether STP Bridge Protocol Data Units
will be processed by the bridge port. When unset, the kernel's
default will be used.
FastLeave=
Takes a boolean. This flag allows the bridge to immediately stop
multicast traffic on a port that receives an IGMP Leave message. It
is only used with IGMP snooping if enabled on the bridge. When
unset, the kernel's default will be used.
AllowPortToBeRoot=
Takes a boolean. Configures whether a given port is allowed to
become a root port. Only used when STP is enabled on the bridge.
When unset, the kernel's default will be used.
ProxyARP=
Takes a boolean. Configures whether proxy ARP to be enabled on this
port. When unset, the kernel's default will be used.
ProxyARPWiFi=
Takes a boolean. Configures whether proxy ARP to be enabled on this
port which meets extended requirements by IEEE 802.11 and Hotspot
2.0 specifications. When unset, the kernel's default will be used.
MulticastRouter=
Configures this port for having multicast routers attached. A port
with a multicast router will receive all multicast traffic. Takes
one of "no" to disable multicast routers on this port, "query" to
let the system detect the presence of routers, "permanent" to
permanently enable multicast traffic forwarding on this port, or
"temporary" to enable multicast routers temporarily on this port,
not depending on incoming queries. When unset, the kernel's default
will be used.
Cost=
Sets the "cost" of sending packets of this interface. Each port in
a bridge may have a different speed and the cost is used to decide
which link to use. Faster interfaces should have lower costs. It is
an integer value between 1 and 65535.
Priority=
Sets the "priority" of sending packets on this interface. Each port
in a bridge may have a different priority which is used to decide
which link to use. Lower value means higher priority. It is an
integer value between 0 to 63. Networkd does not set any default,
meaning the kernel default value of 32 is used.
[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.
Destination=
Takes an IP address of the destination VXLAN tunnel endpoint.
VLANId=
The VLAN ID for the new static MAC table entry. If omitted, no VLAN
ID information is appended to the new static MAC table entry.
VNI=
The VXLAN Network Identifier (or VXLAN Segment ID) to use to
connect to the remote VXLAN tunnel endpoint. Takes a number in the
range 1-16777215. Defaults to unset.
AssociatedWith=
Specifies where the address is associated with. Takes one of "use",
"self", "master" or "router". "use" means the address is in use.
User space can use this option to indicate to the kernel that the
fdb entry is in use. "self" means the address is associated with
the port drivers fdb. Usually hardware. "master" means the address
is associated with master devices fdb. "router" means the
destination address is associated with a router. Note that it's
valid if the referenced device is a VXLAN type device and has route
shortcircuit enabled. Defaults to "self".
[CAN] SECTION OPTIONS
The "[CAN]" section manages the Controller Area Network (CAN bus) and
accepts the following keys.
BitRate=
The bitrate of CAN device in bits per second. The usual SI prefixes
(K, M) with the base of 1000 can be used here.
SamplePoint=
Optional sample point in percent with one decimal (e.g. "75%",
"87.5%") or permille (e.g. "875<permille>").
RestartSec=
Automatic restart delay time. If set to a non-zero value, a restart
of the CAN controller will be triggered automatically in case of a
bus-off condition after the specified delay time. Subsecond delays
can be specified using decimals (e.g. "0.1s") or a "ms" or "us"
postfix. Using "infinity" or "0" will turn the automatic restart
off. By default automatic restart is disabled.
TripleSampling=
Takes a boolean. When "yes", three samples (instead of one) are
used to determine the value of a received bit by majority rule.
When unset, the kernel's default will be used.
[QDISC] SECTION OPTIONS
The "[QDisc]" section manages the traffic control queueing discipline
(qdisc).
Parent=
Specifies the parent Queueing Discipline (qdisc). Takes one of
"clsact" or "ingress". This is mandatory.
Handle=
Specifies the major number of unique identifier of the qdisc, known
as the handle. Takes a number in hexadecimal ranges 1 to ffff.
Defaults to unset.
[NETWORKEMULATOR] SECTION OPTIONS
The "[NetworkEmulator]" section manages the queueing discipline (qdisc)
of the network emulator. It can be used to configure the kernel packet
scheduler and simulate packet delay and loss for UDP or TCP
applications, or limit the bandwidth usage of a particular service to
simulate internet connections.
Parent=
Specifies the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact" or "ingress". Defaults to "root".
Handle=
Specifies the major number of unique identifier of the qdisc, known
as the handle. Takes a number in hexadecimal ranges 1 to ffff.
Defaults to unset.
DelaySec=
Specifies the fixed amount of delay to be added to all packets
going out of the interface. Defaults to unset.
DelayJitterSec=
Specifies the chosen delay to be added to the packets outgoing to
the network interface. Defaults to unset.
PacketLimit=
Specifies the maximum number of packets the qdisc may hold queued
at a time. An unsigned integer ranges 0 to 4294967294. Defaults to
1000.
LossRate=
Specifies an independent loss probability to be added to the
packets outgoing from the network interface. Takes a percentage
value, suffixed with "%". Defaults to unset.
DuplicateRate=
Specifies that the chosen percent of packets is duplicated before
queuing them. Takes a percentage value, suffixed with "%". Defaults
to unset.
[TOKENBUCKETFILTER] SECTION OPTIONS
The "[TokenBucketFilter]" section manages the queueing discipline
(qdisc) of token bucket filter (tbf).
Parent=
Specifies the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact" or "ingress". Defaults to "root".
Handle=
Specifies the major number of unique identifier of the qdisc, known
as the handle. Takes a number in hexadecimal ranges 1 to ffff.
Defaults to unset.
LatencySec=
Specifies the latency parameter, which specifies the maximum amount
of time a packet can sit in the Token Bucket Filter (TBF). Defaults
to unset.
LimitSize=
Takes the number of bytes that can be queued waiting for tokens to
become available. When the size is suffixed with K, M, or G, it is
parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the
base of 1000. Defaults to unset.
Burst=
Specifies the size of the bucket. This is the maximum amount of
bytes that tokens can be available for instantaneous transfer. When
the size is suffixed with K, M, or G, it is parsed as Kilobytes,
Megabytes, or Gigabytes, respectively, to the base of 1000.
Defaults to unset.
Rate=
Specifies the device specific bandwidth. When suffixed with K, M,
or G, the specified bandwidth is parsed as Kilobits, Megabits, or
Gigabits, respectively, to the base of 1000. Defaults to unset.
MPUBytes=
The Minimum Packet Unit (MPU) determines the minimal token usage
(specified in bytes) for a packet. When suffixed with K, M, or G,
the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
respectively, to the base of 1000. Defaults to zero.
PeakRate=
Takes the maximum depletion rate of the bucket. When suffixed with
K, M, or G, the specified size is parsed as Kilobits, Megabits, or
Gigabits, respectively, to the base of 1000. Defaults to unset.
MTUBytes=
Specifies the size of the peakrate bucket. When suffixed with K, M,
or G, the specified size is parsed as Kilobytes, Megabytes, or
Gigabytes, respectively, to the base of 1000. Defaults to unset.
[STOCHASTICFAIRNESSQUEUEING] SECTION OPTIONS
The "[StochasticFairnessQueueing]" section manages the queueing
discipline (qdisc) of stochastic fairness queueing (sfq).
Parent=
Specifies the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact" or "ingress". Defaults to "root".
Handle=
Specifies the major number of unique identifier of the qdisc, known
as the handle. Takes a number in hexadecimal ranges 1 to ffff.
Defaults to unset.
PerturbPeriodSec=
Specifies the interval in seconds for queue algorithm perturbation.
Defaults to unset.
[CONTROLLEDDELAY] SECTION OPTIONS
The "[ControlledDelay]" section manages the queueing discipline (qdisc)
of controlled delay (CoDel).
Parent=
Specifies the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact" or "ingress". Defaults to "root".
Handle=
Specifies the major number of unique identifier of the qdisc, known
as the handle. Takes a number in hexadecimal ranges 1 to ffff.
Defaults to unset.
PacketLimit=
Specifies the hard limit on the queue size in number of packets.
When this limit is reached, incoming packets are dropped. An
unsigned integer ranges 0 to 4294967294. Defaults to unset and
kernel's default is used.
TargetSec=
Takes a timespan. Specifies the acceptable minimum
standing/persistent queue delay. Defaults to unset and kernel's
default is used.
IntervalSec=
Takes a timespan. This is used to ensure that the measured minimum
delay does not become too stale. Defaults to unset and kernel's
default is used.
ECN=
Takes a boolean. This can be used to mark packets instead of
dropping them. Defaults to unset and kernel's default is used.
CEThresholdSec=
Takes a timespan. This sets a threshold above which all packets are
marked with ECN Congestion Experienced (CE). Defaults to unset and
kernel's default is used.
[FAIRQUEUEINGCONTROLLEDDELAY] SECTION OPTIONS
The "[FairQueueingControlledDelay]" section manages the queueing
discipline (qdisc) of fair queuing controlled delay (FQ-CoDel).
Parent=
Specifies the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact" or "ingress". Defaults to "root".
Handle=
Specifies the major number of unique identifier of the qdisc, known
as the handle. Takes a number in hexadecimal ranges 1 to ffff.
Defaults to unset.
PacketLimit=
Specifies the hard limit on the real queue size. When this limit is
reached, incoming packets are dropped. Defaults to unset and
kernel's default is used.
MemoryLimit=
Specifies the limit on the total number of bytes that can be queued
in this FQ-CoDel instance. When suffixed with K, M, or G, the
specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
respectively, to the base of 1024. Defaults to unset and kernel's
default is used.
Flows=
Specifies the number of flows into which the incoming packets are
classified. Defaults to unset and kernel's default is used.
TargetSec=
Takes a timespan. Specifies the acceptable minimum
standing/persistent queue delay. Defaults to unset and kernel's
default is used.
IntervalSec=
Takes a timespan. This is used to ensure that the measured minimum
delay does not become too stale. Defaults to unset and kernel's
default is used.
Quantum=
Specifies the number of bytes used as 'deficit' in the fair queuing
algorithmtimespan. When suffixed with K, M, or G, the specified
size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively,
to the base of 1024. Defaults to unset and kernel's default is
used.
ECN=
Takes a boolean. This can be used to mark packets instead of
dropping them. Defaults to unset and kernel's default is used.
CEThresholdSec=
Takes a timespan. This sets a threshold above which all packets are
marked with ECN Congestion Experienced (CE). Defaults to unset and
kernel's default is used.
[FAIRQUEUEING] SECTION OPTIONS
The "[FairQueueing]" section manages the queueing discipline (qdisc) of
fair queue traffic policing (FQ).
Parent=
Specifies the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact" or "ingress". Defaults to "root".
Handle=
Specifies the major number of unique identifier of the qdisc, known
as the handle. Takes a number in hexadecimal ranges 1 to ffff.
Defaults to unset.
PacketLimit=
Specifies the hard limit on the real queue size. When this limit is
reached, incoming packets are dropped. Defaults to unset and
kernel's default is used.
FlowLimit=
Specifies the hard limit on the maximum number of packets queued
per flow. Defaults to unset and kernel's default is used.
Quantum=
Specifies the credit per dequeue RR round, i.e. the amount of bytes
a flow is allowed to dequeue at once. When suffixed with K, M, or
G, the specified size is parsed as Kilobytes, Megabytes, or
Gigabytes, respectively, to the base of 1024. Defaults to unset and
kernel's default is used.
InitialQuantum=
Specifies the initial sending rate credit, i.e. the amount of bytes
a new flow is allowed to dequeue initially. When suffixed with K,
M, or G, the specified size is parsed as Kilobytes, Megabytes, or
Gigabytes, respectively, to the base of 1024. Defaults to unset and
kernel's default is used.
MaximumRate=
Specifies the maximum sending rate of a flow. When suffixed with K,
M, or G, the specified size is parsed as Kilobits, Megabits, or
Gigabits, respectively, to the base of 1000. Defaults to unset and
kernel's default is used.
Buckets=
Specifies the size of the hash table used for flow lookups.
Defaults to unset and kernel's default is used.
OrphanMask=
Takes an unsigned integer. For packets not owned by a socket, fq is
able to mask a part of hash and reduce number of buckets associated
with the traffic. Defaults to unset and kernel's default is used.
Pacing=
Takes a boolean, and enables or disables flow pacing. Defaults to
unset and kernel's default is used.
CEThresholdSec=
Takes a timespan. This sets a threshold above which all packets are
marked with ECN Congestion Experienced (CE). Defaults to unset and
kernel's default is used.
[TRIVIALLINKEQUALIZER] SECTION OPTIONS
The "[TrivialLinkEqualizer]" section manages the queueing discipline
(qdisc) of trivial link equalizer (teql).
Parent=
Specifies the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact" or "ingress". Defaults to "root".
Handle=
Specifies the major number of unique identifier of the qdisc, known
as the handle. Takes a number in hexadecimal ranges 1 to ffff.
Defaults to unset.
Id=
Specifies the interface ID "N" of teql. Defaults to "0". Note that
when teql is used, currently, the module sch_teql with
max_equalizers=N+1 option must be loaded before systemd-networkd is
started.
[BRIDGEVLAN] SECTION OPTIONS
The "[BridgeVLAN]" section manages the VLAN ID configuration of a
bridge port and accepts the following keys. Specify several
"[BridgeVLAN]" sections to configure several VLAN entries. The
VLANFiltering= option has to be enabled, see "[Bridge]" section in
systemd.netdev(5).
VLAN=
The VLAN ID allowed on the port. This can be either a single ID or
a range M-N. VLAN IDs are valid from 1 to 4094.
EgressUntagged=
The VLAN ID specified here will be used to untag frames on egress.
Configuring EgressUntagged= implicates the use of VLAN= above and
will enable the VLAN ID for ingress as well. This can be either a
single ID or a range M-N.
PVID=
The Port VLAN ID specified here is assigned to all untagged frames
at ingress. PVID= can be used only once. Configuring PVID=
implicates the use of VLAN= above and will enable the VLAN ID for
ingress as well.
EXAMPLES
Example 1. Static network configuration
# /etc/systemd/network/50-static.network
[Match]
Name=enp2s0
[Network]
Address=192.168.0.15/24
Gateway=192.168.0.1
This brings interface "enp2s0" up with a static address. The specified
gateway will be used for a default route.
Example 2. DHCP on ethernet links
# /etc/systemd/network/80-dhcp.network
[Match]
Name=en*
[Network]
DHCP=yes
This will enable DHCPv4 and DHCPv6 on all interfaces with names
starting with "en" (i.e. ethernet interfaces).
Example 3. IPv6 Prefix Delegation
# /etc/systemd/network/55-ipv6-pd-upstream.network
[Match]
Name=enp1s0
[Network]
DHCP=ipv6
# /etc/systemd/network/56-ipv6-pd-downstream.network
[Match]
Name=enp2s0
[Network]
IPv6PrefixDelegation=dhcpv6
This will enable IPv6 PD on the interface enp1s0 as an upstream
interface where the DHCPv6 client is running and enp2s0 as a downstream
interface where the prefix is delegated to.
Example 4. A bridge with two enslaved links
# /etc/systemd/network/25-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/25-bridge-slave-interface-1.network
[Match]
Name=enp2s0
[Network]
Bridge=bridge0
# /etc/systemd/network/25-bridge-slave-interface-2.network
[Match]
Name=wlp3s0
[Network]
Bridge=bridge0
This creates a bridge and attaches devices "enp2s0" and "wlp3s0" to it.
The bridge will have the specified static address and network assigned,
and a default route via the specified gateway will be added. The
specified DNS server will be added to the global list of DNS resolvers.
Example 5.
# /etc/systemd/network/20-bridge-slave-interface-vlan.network
[Match]
Name=enp2s0
[Network]
Bridge=bridge0
[BridgeVLAN]
VLAN=1-32
PVID=42
EgressUntagged=42
[BridgeVLAN]
VLAN=100-200
[BridgeVLAN]
EgressUntagged=300-400
This overrides the configuration specified in the previous example for
the interface "enp2s0", and enables VLAN on that bridge port. VLAN IDs
1-32, 42, 100-400 will be allowed. Packets tagged with VLAN IDs 42,
300-400 will be untagged when they leave on this interface. Untagged
packets which arrive on this interface will be assigned VLAN ID 42.
Example 6. Various tunnels
/etc/systemd/network/25-tunnels.network
[Match]
Name=ens1
[Network]
Tunnel=ipip-tun
Tunnel=sit-tun
Tunnel=gre-tun
Tunnel=vti-tun
/etc/systemd/network/25-tunnel-ipip.netdev
[NetDev]
Name=ipip-tun
Kind=ipip
/etc/systemd/network/25-tunnel-sit.netdev
[NetDev]
Name=sit-tun
Kind=sit
/etc/systemd/network/25-tunnel-gre.netdev
[NetDev]
Name=gre-tun
Kind=gre
/etc/systemd/network/25-tunnel-vti.netdev
[NetDev]
Name=vti-tun
Kind=vti
This will bring interface "ens1" up and create an IPIP tunnel, a SIT
tunnel, a GRE tunnel, and a VTI tunnel using it.
Example 7. A bond device
# /etc/systemd/network/30-bond1.network
[Match]
Name=bond1
[Network]
DHCP=ipv6
# /etc/systemd/network/30-bond1.netdev
[NetDev]
Name=bond1
Kind=bond
# /etc/systemd/network/30-bond1-dev1.network
[Match]
MACAddress=52:54:00:e9:64:41
[Network]
Bond=bond1
# /etc/systemd/network/30-bond1-dev2.network
[Match]
MACAddress=52:54:00:e9:64:42
[Network]
Bond=bond1
This will create a bond device "bond1" and enslave the two devices with
MAC addresses 52:54:00:e9:64:41 and 52:54:00:e9:64:42 to it. IPv6 DHCP
will be used to acquire an address.
Example 8. Virtual Routing and Forwarding (VRF)
Add the "bond1" interface to the VRF master interface "vrf1". This will
redirect routes generated on this interface to be within the routing
table defined during VRF creation. For kernels before 4.8 traffic won't
be redirected towards the VRFs routing table unless specific ip-rules
are added.
# /etc/systemd/network/25-vrf.network
[Match]
Name=bond1
[Network]
VRF=vrf1
Example 9. MacVTap
This brings up a network interface "macvtap-test" and attaches it to
"enp0s25".
# /lib/systemd/network/25-macvtap.network
[Match]
Name=enp0s25
[Network]
MACVTAP=macvtap-test
Example 10. A Xfrm interface with physical underlying device.
# /etc/systemd/network/27-xfrm.netdev
[NetDev]
Name=xfrm0
[Xfrm]
InterfaceId=7
# /etc/systemd/network/27-eth0.network
[Match]
Name=eth0
[Network]
Xfrm=xfrm0
This creates a "xfrm0" interface and binds it to the "eth0" device.
This allows hardware based ipsec offloading to the "eth0" nic. If
offloading is not needed, xfrm interfaces can be assigned to the "lo"
device.
SEE ALSO
systemd(1), systemd-networkd.service(8), systemd.link(5),
systemd.netdev(5), systemd-resolved.service(8)
NOTES
1. RFC 7217
https://tools.ietf.org/html/rfc7217
2. Link-Local Multicast Name Resolution
https://tools.ietf.org/html/rfc4795
3. Multicast DNS
https://tools.ietf.org/html/rfc6762
4. DNS-over-TLS
https://tools.ietf.org/html/rfc7858
5. DNSSEC
https://tools.ietf.org/html/rfc4033
6. IEEE 802.1AB-2016
https://standards.ieee.org/findstds/standard/802.1AB-2016.html
7. ip-sysctl.txt
https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt
8. RFC 4941
https://tools.ietf.org/html/rfc4941
9. RFC 1027
https://tools.ietf.org/html/rfc1027
10. RFC 6275
https://tools.ietf.org/html/rfc6275
11. RFC 5224
https://tools.ietf.org/html/rfc5227
12. RFC 4862
https://tools.ietf.org/html/rfc4862
13. RFC 3041
https://tools.ietf.org/html/rfc3041
14. RFC 3484
https://tools.ietf.org/html/rfc3484
15. RFC4191
https://tools.ietf.org/html/rfc4191
16. RFC 7844
https://tools.ietf.org/html/rfc7844
17. C-style escapes
https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences
18. RFC 3315
https://tools.ietf.org/html/rfc3315#section-17.2.1
19. RFC 7084
https://tools.ietf.org/html/rfc7084
20. RFC 4861
https://tools.ietf.org/html/rfc4861
systemd 245 SYSTEMD.NETWORK(5)