systemd.networksystemdsystemd.network5systemd.networkNetwork configurationnetwork.networkDescriptionA plain ini-style text file that encodes network configuration for matching network interfaces,
used by
systemd-networkd8.
See systemd.syntax7
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 /usr/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 /usr/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 /usr/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 OptionsThe 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: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 once, in which case the
lists are merged. If the empty string is assigned to this option, the list is reset.[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.Group=Link groups are similar to port ranges found in managed switches.
When network interfaces are added to a numbered group, operations on
all the interfaces from that group can be performed at once. An unsigned
integer in the range 0—4294967294. Defaults to unset.RequiredForOnline=Takes a boolean or a minimum operational state and an optional maximum operational state.
Please see networkctl1
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.[SR-IOV] Section OptionsThe [SR-IOV] section accepts the following keys. Specify several [SR-IOV] sections to configure
several SR-IOVs. SR-IOV provides the ability to partition a single physical PCI resource into virtual
PCI functions which can then be injected into a VM. In the case of network VFs, SR-IOV improves
north-south network performance (that is, traffic with endpoints outside the host machine) by allowing
traffic to bypass the host machine’s network stack.VirtualFunction=Specifies a Virtual Function (VF), lightweight PCIe function designed solely to move data
in and out. Takes an unsigned integer in the range 0..2147483646. This option is compulsory.VLANId=Specifies VLAN ID of the virtual function. Takes an unsigned integer in the range 1..4095.QualityOfService=Specifies quality of service of the virtual function. Takes an unsigned integer in the range 1..4294967294.VLANProtocol=Specifies VLAN protocol of the virtual function. Takes 802.1Q or
802.1ad.MACSpoofCheck=Takes a boolean. Controls the MAC spoof checking. When unset, the kernel's default will be used.QueryReceiveSideScaling=Takes a boolean. Toggle the ability of querying the receive side scaling (RSS)
configuration of the virtual function (VF). The VF RSS information like RSS hash key may be
considered sensitive on some devices where this information is shared between VF and the
physical function (PF). When unset, the kernel's default will be used.Trust=Takes a boolean. Allows to set trust mode of the virtual function (VF). When set, VF
users can set a specific feature which may impact security and/or performance. When unset,
the kernel's default will be used.LinkState=Allows to set the link state of the virtual function (VF). Takes a boolean or a
special value auto. Setting to auto means a
reflection of the physical function (PF) link state, yes lets the VF to
communicate with other VFs on this host even if the PF link state is down,
no causes the hardware to drop any packets sent by the VF. When unset,
the kernel's default will be used.MACAddress=Specifies the MAC address for the virtual function.[Network] Section OptionsThe [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 below.See the [DHCPv4] or [DHCPv6] sections 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.
IPv6LinkLocalAddressGenerationMode=Specifies how IPv6 link local address is generated. Takes one of eui64,
none, stable-privacy and random.
When unset, the kernel's default will be used. Note that if LinkLocalAdressing=
not configured as ipv6 then IPv6LinkLocalAddressGenerationMode=
is ignored.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 veth99IPv6Token=Specifies an optional address generation mode for the Stateless Address
Autoconfiguration (SLAAC). Supported modes are prefixstable and
static.When the mode is set to static, an IPv6 address must be
specified after a colon (:), and the lower bits of the supplied
address are combined with the upper bits of a prefix received in a Router Advertisement
(RA) 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 by 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. If an IPv6 address without mode is specified, then
static mode is assumed.When the mode is set to prefixstable the
RFC 7217 algorithm for generating
interface identifiers will be used. This mode can optionally take an IPv6 address separated
with a colon (:). If an IPv6 address is specified, then an interface
identifier is generated only when a prefix received in an RA message matches the supplied
address.If no address generation mode is specified (which is the default), or a received
prefix does not match any of the addresses provided in prefixstable
mode, 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 uses both the interface
name and MAC address as input to the hash 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.This setting can be specified multiple times. If an empty string is assigned, then
the all previous assignments are cleared.Examples:
IPv6Token=::1a:2b:3c:4d
IPv6Token=static:::1a:2b:3c:4d
IPv6Token=prefixstable
IPv6Token=prefixstable:2002:da8:1::LLMNR=Takes 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 host registration and announcement. Defaults to
true. This setting is read by
systemd-resolved.service8.MulticastDNS=Takes a boolean or resolve. When true,
enables Multicast
DNS 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.service8.DNSOverTLS=Takes a boolean or opportunistic.
When true, enables
DNS-over-TLS
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.conf5's
global DNSOverTLS= option. Defaults to
false. This setting is read by
systemd-resolved.service8.DNSSEC=Takes a boolean or allow-downgrade. When true, enables
DNSSEC
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.conf5's
global DNSSEC= option. Defaults to
false. This setting is read by
systemd-resolved.service8.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.service8.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
networkctl1 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 hostname, the local machine ID (as stored
in machine-id5) and the
local interface name, as well as the pretty hostname of the system (as set in
machine-info5). 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. 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_pton3.
This is a short-hand for an [Address] section only
containing an Address key (see below). This option may be
specified more than once.
If the specified address is 0.0.0.0 (for IPv4) or ::
(for IPv6), a new address range of the requested size is automatically allocated from a
system-wide pool of unused ranges. 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_pton3.
This is a short-hand for a [Route] section only containing
a Gateway key. This option may be specified more than
once.DNS=A DNS server address, which must be in the format
described in
inet_pton3.
This option may be specified more than once. Each address can optionally take a port number
separated with :, a network interface name or index separated with
%, and a Server Name Indication (SNI) separated with #.
When IPv6 address is specified with a port number, then the address must be in the square
brackets. That is, the acceptable full formats are
111.222.333.444:9953%ifname#example.com for IPv4 and
[1111:2222::3333]:9953%ifname#example.com for IPv6. This setting can be
specified multiple times. If an empty string is assigned, then the all previous assignments
are cleared. This setting is read by
systemd-resolved.service8.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 hostnames (hostnames containing no dots) to become fully qualified
domain names (FQDNs). If a single-label hostname 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 hostnames
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.service8.
"Search domains" correspond to the domain and search entries in
resolv.conf5.
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 (either an IP address, or a hostname). This option may be specified more than once. This setting is read by
systemd-timesyncd.service8.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
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,
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 addressing is disabled.Further settings for the IPv6 RA support may be configured in the [IPv6AcceptRA] section, see
below.Also see ip-sysctl.txt 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.
IPv4AcceptLocal=Takes a boolean. Accept packets with local source addresses. In combination
with suitable routing, this can be used to direct packets between two local interfaces over
the wire and have them accepted properly. 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.
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
entries to the kernel's IPv6 neighbor proxy table.
This option implies but has no effect if
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.netdev5.
Bond=The name of the bond to add the link to. See
systemd.netdev5.
VRF=The name of the VRF to add the link to. See
systemd.netdev5.
VLAN=The name of a VLAN to create on the link. See
systemd.netdev5.
This option may be specified more than once.IPVLAN=The name of a IPVLAN to create on the link. See
systemd.netdev5.
This option may be specified more than once.MACVLAN=The name of a MACVLAN to create on the link. See
systemd.netdev5.
This option may be specified more than once.VXLAN=The name of a VXLAN to create on the link. See
systemd.netdev5.
This option may be specified more than once.Tunnel=The name of a Tunnel to create on the link. See
systemd.netdev5.
This option may be specified more than once.MACsec=The name of a MACsec device to create on the link. See
systemd.netdev5.
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. If is not explicitly set, it will
default to this value.
IgnoreCarrierLoss=Takes a boolean. Allows networkd to retain both the static and dynamic configuration
of the interface even if its carrier is lost. When unset, the value specified with
is used.
Xfrm=The name of the xfrm to create on the link. See
systemd.netdev5.
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 OptionsAn [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_pton3.
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 in the range 0—255.
Defaults to global.HomeAddress=Takes a boolean. Designates this address the "home address" as defined in
RFC 6275.
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.
When ipv6, performs IPv6 Duplicate Address Detection. See
RFC 4862.
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. 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 OptionsA [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 OptionsAn [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. Precedence is managed by userspace,
and only the label itself is stored in the kernelLabel=The label for the prefix, an unsigned integer in the range 0–4294967294.
0xffffffff is reserved. This setting is mandatory.Prefix=IPv6 prefix is an address with a prefix length, separated by a slash / character.
This key is mandatory. [RoutingPolicyRule] Section OptionsAn [RoutingPolicyRule] section accepts the following keys. Specify several [RoutingPolicyRule]
sections to configure several rules.TypeOfService=Takes a number between 0 and 255 that specifies the type of service to match.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 OptionsThe [NextHop] section is used to manipulate entries in the kernel's "nexthop" tables. The
[NextHop] section accepts the following keys. Specify several [NextHop] sections to configure several
hops.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 OptionsThe [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 RFC 4191 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_pton3.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 OptionsThe [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
option in resolv.conf5.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.service and take precedence over any statically configured
ones.UseSIP=When true (the default), the SIP servers received from the DHCP server will be collected
and made available to client programs.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
(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.link5).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.MUDURL=When configured, the Manufacturer Usage Descriptions (MUD) URL will be sent to the
DHCPv4 server. Takes an URL of length up to 255 characters. A superficial verification that
the string is a valid URL will be performed. DHCPv4 clients are intended to have at most one
MUD URL associated with them. See
RFC 8520.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 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 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 hostnames, 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 option in resolv.conf5.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
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.conf5
for a description of possible values.DUIDRawData=Override the global DUIDRawData setting for this network. See
networkd.conf5
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. Defaults to 1024.RouteTable=numThe 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 when this parameter is not 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.FallbackLeaseLifetimeSec=Allows to set DHCPv4 lease lifetime when DHCPv4 server does not send the lease lifetime.
Takes one of forever or infinity means that the address
never expires. Defaults to unset.SendRelease=When true, the DHCPv4 client sends a DHCP release packet when it stops.
Defaults to true.SendDecline=A boolean. When true, the DHCPv4 client receives the IP address from the
DHCP server. After a new IP is received, the DHCPv4 client performs IPv4 Duplicate Address
Detection. If duplicate use is detected, the DHCPv4 client rejects the IP by sending a
DHCPDECLINE packet and tries to obtain an IP address again. See RFC 5224. Defaults to
unset.DenyList=A whitespace-separated list of IPv4 addresses. DHCP offers from servers in the list are rejected. Note that
if AllowList= is configured then DenyList= is ignored.AllowList=A whitespace-separated list of IPv4 addresses. DHCP offers from servers in the list are accepted.RequestOptions=When configured, allows to set arbitrary request options in the DHCPv4 request options list and will be
sent to the DHCPV4 server. A whitespace-separated list of integers in the range 1..254. Defaults to unset.SendOption=Send an arbitrary raw 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. This setting can be specified multiple times. If an empty string is specified,
then all options specified earlier are cleared. Defaults to unset.SendVendorOption=Send an arbitrary vendor 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. 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 OptionsThe [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.RouteMetric=Set the routing metric for routes specified by the DHCP server. Defaults to 1024.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-message 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 for details.
Defaults to true.MUDURL=When configured, the Manufacturer Usage Descriptions (MUD) URL will be sent to the DHCPV6 server.
Takes an URL of length up to 255 characters. A superficial verification that the string is a valid URL
will be performed. DHCPv6 clients are intended to have at most one MUD URL associated with them. See
RFC 8520.RequestOptions=When configured, allows to set arbitrary request options in the DHCPv6 request options list and will
sent to the DHCPV6 server. A whitespace-separated list of integers in the range 1..254. Defaults to unset.SendVendorOption=Send an arbitrary vendor option in the DHCPv6 request. Takes an enterprise identifier, DHCP
option number, data type, and data separated with a colon (enterprise
identifier:option:type:
value). Enterprise identifier is an unsigned integer in the
range 1–4294967294. The option number must be an integer in the range 1–254. Data type takes one
of uint8, uint16, uint32,
ipv4address, ipv6address, or
string. Special characters in the data string may be escaped using C-style
escapes. This setting can be specified multiple times. If an empty string is specified,
then all options specified earlier are cleared. Defaults to unset.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, 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 in the same format as the
Address= in the [Network] section. The DHCPv6 client will include a prefix
hint in the DHCPv6 solicitation sent to the server. The prefix length must be in the range
1–128. Defaults to unset.WithoutRA=Allows DHCPv6 client to start without router advertisements's managed or other address
configuration flag. Takes one of solicit or
information-request. Defaults to unset.SendOption=As in the [DHCPv4] section, however because DHCPv6 uses 16-bit fields to store
option numbers, the option number is an integer in the range 1..65536.UserClass=A DHCPv6 client can use User Class 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. Special characters in the data string may be escaped using
C-style
escapes. This setting can be specified multiple times. If an empty string is specified,
then all options specified earlier are cleared. Takes a whitespace-separated list of strings. Note that
currently NUL bytes are not allowed.VendorClass=A DHCPv6 client can use VendorClass option to identify the vendor that
manufactured the hardware on which the client is running. The information
contained in the data area of this option is contained in one or more opaque
fields that identify details of the hardware configuration. Takes a
whitespace-separated list of strings.[DHCPv6PrefixDelegation] Section OptionsThe [DHCPv6PrefixDelegation] section configures delegated prefix assigned by DHCPv6 server.
The settings in this section are used only when IPv6PrefixDelegation= setting is
enabled, or set to dhcp6.SubnetId=Configure a specific subnet ID on the interface from a (previously) received prefix
delegation. You can either set "auto" (the default) or a specific subnet ID (as defined in
RFC 4291, section
2.5.4), in which case the allowed value is hexadecimal, from 0 to 0x7fffffffffffffff
inclusive. This option is only effective when used together with
IPv6PrefixDelegation= and the corresponding configuration on the upstream
interface.Assign=Takes a boolean. Specifies whether to add an address from the delegated prefixes which
are received from the WAN interface by the IPv6PrefixDelegation=. When
true (on LAN interfce), the EUI-64 algorithm will be used to form an interface identifier
from the delegated prefixes. Defaults to true.Token=Specifies an optional address generation mode for Assign=. Takes an
IPv6 address. When set, the lower bits of the supplied address are combined with the upper
bits of a delegatad prefix received from the WAN interface by the
IPv6PrefixDelegation= prefixes to form a complete address.[IPv6AcceptRA] Section OptionsThe [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 option in resolv.conf5.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 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 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 hostnames, 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 option in resolv.conf5.RouteTable=numThe 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.DenyList=A whitespace-separated list of IPv6 prefixes. IPv6 prefixes supplied via router advertisements in the list are ignored.DHCPv6Client=Takes a boolean, or the special value always. When true (the default), the DHCPv6 client will be started when the
RA has the managed or other information flag. If set to always, the DHCPv6 client will be started even if there is no
managed or other information flag in the RA.[DHCPServer] Section OptionsThe [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=EmitDNS= 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 server information at a later point. If no
suitable uplinkg interface is found the DNS server data from /etc/resolv.conf is
used. 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=EmitSIP=SIP=EmitPOP3=POP3=EmitSMTP=SMTP=EmitLPR=LPR=Similar to the EmitDNS= and DNS= settings
described above, these settings configure whether and what server information for the indicate
protocol 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, ipv6address, or
string. Special characters in the data string may be escaped using
C-style
escapes. This setting can be specified multiple times. If an empty string is specified,
then all options specified earlier are cleared. Defaults to unset.SendVendorOption=Send a vendor 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. 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 OptionsThe [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
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 OptionsOne or more [IPv6Prefix] sections contain the IPv6 prefixes that are announced via Router
Advertisements. See RFC 4861 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).Assign=Takes a boolean. When true, adds an address from the prefix. Default to false.
[IPv6RoutePrefix] Section OptionsOne or more [IPv6RoutePrefix] sections contain the IPv6
prefix routes that are announced via Router Advertisements. See
RFC 4191
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 OptionsThe [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, then 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 OptionsThe [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.[BridgeMDB] Section OptionsThe [BridgeMDB] section manages the multicast membership entries forwarding database table of a port and accepts the following
keys. Specify several [BridgeMDB] sections to configure several permanent multicast membership entries.MulticastGroupAddress=Specifies the IPv4 or IPv6 multicast group address to add. This setting is mandatory.VLANId=The VLAN ID for the new entry. Valid ranges are 0 (no VLAN) to 4094. Optional, defaults to 0.[LLDP] Section OptionsThe [LLDP] section manages the Link Layer Discovery Protocol (LLDP) and accepts the following
keys.MUDURL=Controls support for Ethernet LLDP packet's Manufacturer Usage Description (MUD). MUD is an embedded software
standard defined by the IETF that allows IoT Device makers to advertise device specifications, including the intended
communication patterns for their device when it connects to the network. The network can then use this intent to author
a context-specific access policy, so the device functions only within those parameters. Takes an URL of length up to 255
characters. A superficial verification that the string is a valid URL
will be performed. See
RFC 8520 for details. The MUD URL received
from the LLDP packets will be saved at the state files and can be read via
sd_lldp_neighbor_get_mud_url() function.[CAN] Section OptionsThe [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. Takes a number in the range 1..4294967295.SamplePoint=Optional sample point in percent with one decimal (e.g. 75%,
87.5%) or permille (e.g. 875‰).DataBitRate=DataSamplePoint=The bitrate and sample point for the data phase, if CAN-FD is used. These settings are
analogous to the BitRate= and SamplePoint= keys.FDMode=Takes a boolean. When yes, CAN-FD mode is enabled for the interface.
Note, that a bitrate and optional sample point should also be set for the CAN-FD data phase using
the DataBitRate= and DataSamplePoint= keys.FDNonISO=Takes a boolean. When yes, non-ISO CAN-FD mode is enabled for the
interface. When unset, the kernel's default will be used.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.Termination=Takes a boolean. When yes, the termination resistor will be selected for
the bias network. When unset, the kernel's default will be used.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.ListenOnly=Takes a boolean. When yes, listen-only mode is enabled. When the
interface is in listen-only mode, the interface neither transmit CAN frames nor send ACK
bit. Listen-only mode is important to debug CAN networks without interfering with the
communication or acknowledge the CAN frame. When unset, the kernel's default will be used.
[QDisc] Section OptionsThe [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.[NetworkEmulator] Section OptionsThe [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.
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 in the range 0–4294967294. 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 OptionsThe [TokenBucketFilter] section manages the queueing discipline (qdisc) of token bucket filter
(tbf).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.LimitBytes=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 1024. Defaults to unset.BurstBytes=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 1024. 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 1024. 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 1024.
Defaults to unset.[PIE] Section OptionsThe [PIE] section manages the queueing discipline (qdisc) of Proportional Integral
controller-Enhanced (PIE).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 in the range 1–4294967294. Defaults to unset and kernel's default is used.[FlowQueuePIE] Section OptionsThe [FlowQueuePIE] section manages the queueing discipline
(qdisc) of Flow Queue Proportional Integral controller-Enhanced (fq_pie).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 1 to 4294967294. Defaults to unset and kernel's default is used.[StochasticFairBlue] Section OptionsThe [StochasticFairBlue] section manages the queueing discipline (qdisc) of stochastic fair blue
(sfb).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 in the range 0–4294967294. Defaults to unset and
kernel's default is used.[StochasticFairnessQueueing] Section OptionsThe [StochasticFairnessQueueing] section manages the queueing discipline (qdisc) of stochastic
fairness queueing (sfq).PerturbPeriodSec=Specifies the interval in seconds for queue algorithm perturbation. Defaults to unset.[BFIFO] Section OptionsThe [BFIFO] section manages the queueing discipline (qdisc) of Byte limited Packet First In First
Out (bfifo).LimitBytes=Specifies the hard limit on the FIFO size in bytes. The size limit (a buffer size) to prevent
it from overflowing in case it is unable to dequeue packets as quickly as it receives them. When
this limit is reached, incoming packets are dropped. 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.[PFIFO] Section OptionsThe [PFIFO] section manages the queueing discipline (qdisc) of Packet First In First Out
(pfifo).PacketLimit=Specifies the hard limit on the FIFO size in number of packets. The size limit (a buffer
size) to prevent it from overflowing in case it is unable to dequeue packets as quickly as it
receives them. When this limit is reached, incoming packets are dropped. An unsigned integer in the
range 0–4294967294. Defaults to unset and kernel's default is used.[PFIFOHeadDrop] Section OptionsThe [PFIFOHeadDrop] section manages the queueing discipline (qdisc) of Packet First In First Out
Head Drop (pfifo_head_drop).PacketLimit=As in [PFIFO] section.[PFIFOFast] Section OptionsThe [PFIFOFast] section manages the queueing discipline (qdisc) of Packet First In First Out Fast
(pfifo_fast).[CAKE] Section OptionsThe [CAKE] section manages the queueing discipline (qdisc) of Common Applications Kept Enhanced
(CAKE).OverheadBytes=Specifies that bytes to be addeded to the size of each packet. Bytes may be negative. Takes
an integer in the range from -64 to 256. Defaults to unset and kernel's default is used.Bandwidth=Specifies the shaper bandwidth. 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.[ControlledDelay] Section OptionsThe [ControlledDelay] section manages the queueing discipline (qdisc) of
controlled delay (CoDel).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 in the range 0–4294967294. 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.[DeficitRoundRobinScheduler] Section OptionsThe [DeficitRoundRobinScheduler] section manages the queueing discipline (qdisc) of Deficit Round
Robin Scheduler (DRR).[DeficitRoundRobinSchedulerClass] Section OptionsThe [DeficitRoundRobinSchedulerClass] section manages the traffic control class of Deficit Round
Robin Scheduler (DRR).QuantumBytes=Specifies the amount of bytes a flow is allowed to dequeue before the scheduler moves
to the next class. 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 the MTU of the
interface.[EnhancedTransmissionSelection] Section OptionsThe [EnhancedTransmissionSelection] section manages the queueing discipline (qdisc) of Enhanced
Transmission Selection (ETS).Bands=Specifies the number of bands. An unsigned integer in the range 1–16. This value has to be at
least large enough to cover the strict bands specified through the StrictBands=
and bandwidth-sharing bands specified in QuantumBytes=.StrictBands=Specifies the number of bands that should be created in strict mode. An unsigned integer in
the range 1–16.QuantumBytes=Specifies the white-space separated list of quantum used in band-sharing bands. When
suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
respectively, to the base of 1024. This setting can be specified multiple times. If an empty
string is assigned, then the all previous assignments are cleared.PriorityMap=The priority map maps the priority of a packet to a band. The argument is a white-space
separated list of numbers. The first number indicates which band the packets with priority
0 should be put to, the second is for priority 1, and so on. There can be up to 16 numbers in
the list. If there are fewer, the default band that traffic with one of the unmentioned
priorities goes to is the last one. Each band number must be 0..255. This setting can be
specified multiple times. If an empty string is assigned, then the all previous assignments
are cleared.[GenericRandomEarlyDetection] Section OptionsThe [GenericRandomEarlyDetection] section manages the queueing discipline (qdisc) of Generic Random
Early Detection (GRED).VirtualQueues=Specifies the number of virtual queues. Takes a integer in the range 1-16. Defaults to unset and kernel's default is used.DefaultVirtualQueue=Specifies the number of default virtual queue. This must be less than VirtualQueue=.
Defaults to unset and kernel's default is used.GenericRIO=Takes a boolean. It turns on the RIO-like buffering scheme. Defaults to
unset and kernel's default is used.[FairQueueingControlledDelay] Section OptionsThe [FairQueueingControlledDelay] section manages the queueing discipline (qdisc) of fair queuing
controlled delay (FQ-CoDel).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.MemoryLimitBytes=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.QuantumBytes=Specifies the number of bytes used as the "deficit" in the fair queuing algorithm timespan.
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 OptionsThe [FairQueueing] section manages the queueing discipline (qdisc) of fair queue traffic policing
(FQ).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.QuantumBytes=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.InitialQuantumBytes=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 OptionsThe [TrivialLinkEqualizer] section manages the queueing discipline (qdisc) of trivial link
equalizer (teql).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.[HierarchyTokenBucket] Section OptionsThe [HierarchyTokenBucket] section manages the queueing discipline (qdisc) of hierarchy token
bucket (htb).DefaultClass=Takes the minor id in hexadecimal of the default class. Unclassified traffic gets sent
to the class. Defaults to unset.RateToQuantum=Takes an unsigned integer. The DRR quantums are calculated by dividing the value
configured in Rate= by RateToQuantum=.[HierarchyTokenBucketClass] Section OptionsThe [HierarchyTokenBucketClass] section manages the traffic control class of hierarchy token bucket
(htb).Priority=Specifies the priority of the class. In the round-robin process, classes with the lowest
priority field are tried for packets first.QuantumBytes=Specifies how many bytes to serve from leaf 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.MTUBytes=Specifies the maximum packet size we create. When suffixed with K, M, or G, the specified
size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of 1024.OverheadBytes=Takes an unsigned integer which specifies per-packet size overhead used in rate
computations. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
Megabytes, or Gigabytes, respectively, to the base of 1024.Rate=Specifies the maximum rate this class and all its children are guaranteed. When suffixed
with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits, respectively,
to the base of 1000. This setting is mandatory.CeilRate=Specifies the maximum rate at which a class can send, if its parent has bandwidth to spare.
When suffixed with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits,
respectively, to the base of 1000. When unset, the value specified with Rate=
is used.BufferBytes=Specifies the maximum bytes burst which can be accumulated during idle period. When suffixed
with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively,
to the base of 1024.CeilBufferBytes=Specifies the maximum bytes burst for ceil which can be accumulated during idle period.
When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
respectively, to the base of 1024.[HeavyHitterFilter] Section OptionsThe [HeavyHitterFilter] section manages the queueing discipline (qdisc) of Heavy Hitter Filter
(hhf).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 in the range 0–4294967294. Defaults to unset and
kernel's default is used.[QuickFairQueueing] Section OptionsThe [QuickFairQueueing] section manages the queueing discipline (qdisc) of Quick Fair Queueing
(QFQ).[QuickFairQueueingClass] Section OptionsThe [QuickFairQueueingClass] section manages the traffic control class of Quick Fair Queueing
(qfq).Weight=Specifies the weight of the class. Takes an integer in the range 1..1023. Defaults to
unset in which case the kernel default is used.MaxPacketBytes=Specifies the maximum packet size in bytes for the class. When suffixed with K, M, or G, the specified
size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of 1024. When unset,
the kernel default is used.[BridgeVLAN] Section OptionsThe [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 the [Bridge] section in
systemd.netdev5.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.ExamplesStatic network configuration# /etc/systemd/network/50-static.network
[Match]
Name=enp2s0
[Network]
Address=192.168.0.15/24
Gateway=192.168.0.1This brings interface enp2s0 up with a static address. The
specified gateway will be used for a default route.DHCP on ethernet links# /etc/systemd/network/80-dhcp.network
[Match]
Name=en*
[Network]
DHCP=yesThis will enable DHCPv4 and DHCPv6 on all interfaces with names starting with
en (i.e. ethernet interfaces).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=dhcpv6This 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.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=bridge0This 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.
# /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=300-400This 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.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.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.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
MacVTapThis brings up a network interface macvtap-test
and attaches it to enp0s25.# /usr/lib/systemd/network/25-macvtap.network
[Match]
Name=enp0s25
[Network]
MACVTAP=macvtap-test
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=xfrm0This 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 Alsosystemd1,
systemd-networkd.service8,
systemd.link5,
systemd.netdev5,
systemd-resolved.service8