SYSTEMD.NETWORK(5) systemd.network SYSTEMD.NETWORK(5)
systemd.network - Network configuration
network.network
A plain ini-style text file that encodes network configuration for
matching network interfaces, used by systemd-networkd(8). See
systemd.syntax(7) 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.
The network file contains a [Match] section, which determines if a
given network file may be applied to a given device; and a [Network]
section specifying how the device should be configured. The first (in
lexical order) of the network files that matches a given device is
applied, all later files are ignored, even if they match as well.
A network file is said to match a network interface if all matches
specified by the [Match] section are satisfied. When a network file
does not contain valid settings in [Match] section, then the file
will match all interfaces and systemd-networkd warns about that.
Hint: to avoid the warning and to make it clear that all interfaces
shall be matched, add the following:
Name=*
The following keys are accepted:
MACAddress=
A whitespace-separated list of hardware addresses. Use full
colon-, hyphen- or dot-delimited hexadecimal. See the example
below. This option may appear more than once, in which case the
lists are merged. If the empty string is assigned to this option,
the list of hardware addresses defined prior to this is reset.
Example:
MACAddress=01:23:45:67:89:ab 00-11-22-33-44-55 AABB.CCDD.EEFF
PermanentMACAddress=
A whitespace-separated list of hardware's permanent addresses.
While MACAddress= matches the device's current MAC address, this
matches the device's permanent MAC address, which may be
different from the current one. Use full colon-, hyphen- or
dot-delimited hexadecimal. This option may appear more than once,
in which case the lists are merged. If the empty string is
assigned to this option, the list of hardware addresses defined
prior to this is reset.
Path=
A whitespace-separated list of shell-style globs matching the
persistent path, as exposed by the udev property ID_PATH.
Driver=
A whitespace-separated list of shell-style globs matching the
driver currently bound to the device, as exposed by the udev
property ID_NET_DRIVER of its parent device, or if that is not
set, the driver as exposed by ethtool -i of the device itself. If
the list is prefixed with a "!", the test is inverted.
Type=
A whitespace-separated list of shell-style globs matching the
device type, as exposed by networkctl status. If the list is
prefixed with a "!", the test is inverted.
Property=
A whitespace-separated list of udev property name with its value
after a equal ("="). If multiple properties are specified, the
test results are ANDed. If the list is prefixed with a "!", the
test is inverted. If a value contains white spaces, then please
quote whole key and value pair. If a value contains quotation,
then please escape the quotation with "\".
Example: if a .link file has the following:
Property=ID_MODEL_ID=9999 "ID_VENDOR_FROM_DATABASE=vendor name" "KEY=with \"quotation\""
then, the .link file matches only when an interface has all the
above three properties.
Name=
A whitespace-separated list of shell-style globs matching the
device name, as exposed by the udev property "INTERFACE", or
device's alternative names. If the list is prefixed with a "!",
the test is inverted.
WLANInterfaceType=
A whitespace-separated list of wireless network type. Supported
values are "ad-hoc", "station", "ap", "ap-vlan", "wds",
"monitor", "mesh-point", "p2p-client", "p2p-go", "p2p-device",
"ocb", and "nan". If the list is prefixed with a "!", the test is
inverted.
SSID=
A whitespace-separated list of shell-style globs matching the
SSID of the currently connected wireless LAN. If the list is
prefixed with a "!", the test is inverted.
BSSID=
A whitespace-separated list of hardware address of the currently
connected wireless LAN. Use full colon-, hyphen- or dot-delimited
hexadecimal. See the example in MACAddress=. This option may
appear more than once, in which case the lists are merged. If the
empty string is assigned to this option, the list is reset.
Host=
Matches against the hostname or machine ID of the host. See
ConditionHost= in systemd.unit(5) for details. When prefixed with
an exclamation mark ("!"), the result is negated. If an empty
string is assigned, then previously assigned value is cleared.
Virtualization=
Checks whether the system is executed in a virtualized
environment and optionally test whether it is a specific
implementation. See ConditionVirtualization= in systemd.unit(5)
for details. When prefixed with an exclamation mark ("!"), the
result is negated. If an empty string is assigned, then
previously assigned value is cleared.
KernelCommandLine=
Checks whether a specific kernel command line option is set. See
ConditionKernelCommandLine= in systemd.unit(5) for details. When
prefixed with an exclamation mark ("!"), the result is negated.
If an empty string is assigned, then previously assigned value is
cleared.
KernelVersion=
Checks whether the kernel version (as reported by uname -r)
matches a certain expression. See ConditionKernelVersion= in
systemd.unit(5) for details. When prefixed with an exclamation
mark ("!"), the result is negated. If an empty string is
assigned, then previously assigned value is cleared.
Architecture=
Checks whether the system is running on a specific architecture.
See ConditionArchitecture= in systemd.unit(5) for details. When
prefixed with an exclamation mark ("!"), the result is negated.
If an empty string is assigned, then previously assigned value is
cleared.
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 networkctl(1) for possible
operational states. When "yes", the network is deemed required
when determining whether the system is online when running
systemd-networkd-wait-online. When "no", the network is ignored
when checking for online state. When a minimum operational state
and an optional maximum operational state are set, "yes" is
implied, and this controls the minimum and maximum operational
state required for the network interface to be considered online.
Defaults to "yes".
The network will be brought up normally in all cases, but in the
event that there is no address being assigned by DHCP or the
cable is not plugged in, the link will simply remain offline and
be skipped automatically by systemd-networkd-wait-online if
"RequiredForOnline=no".
The [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.
The [Network] section accepts the following keys:
Description=
A description of the device. This is only used for presentation
purposes.
DHCP=
Enables DHCPv4 and/or DHCPv6 client support. Accepts "yes", "no",
"ipv4", or "ipv6". Defaults to "no".
Note that DHCPv6 will by default be triggered by Router
Advertisement, if that is enabled, regardless of this parameter.
By enabling DHCPv6 support explicitly, the DHCPv6 client will be
started regardless of the presence of routers on the link, or
what flags the routers pass. See "IPv6AcceptRA=".
Furthermore, note that by default the domain name specified
through DHCP is not used for name resolution. See option
UseDomains= below.
See the [DHCPv4] or [DHCPv6] 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 veth99
IPv6Token=
Specifies an optional address generation mode and a required IPv6
address. If the mode is present, the two parts must be separated
with a colon "mode:address". The address generation mode may be
either prefixstable or static. If not specified, static is
assumed.
When the mode is set to static, or unspecified, the lower bits of
the supplied address are combined with the upper bits of a prefix
received in a Router Advertisement message to form a complete
address. Note that if multiple prefixes are received in an RA
message, or in multiple RA messages, addresses will be formed
from each of them using the supplied address. This mode
implements SLAAC but uses a static interface identifier instead
of an identifier generated using the EUI-64 algorithm. Because
the interface identifier is static, if Duplicate Address
Detection detects that the computed address is a duplicate (in
use by another node on the link), then this mode will fail to
provide an address for that prefix.
When the mode is set to "prefixstable" the RFC 7217 algorithm for
generating interface identifiers will be used, but only when a
prefix received in an RA message matches the supplied address.
See RFC 7217[1]. Prefix matching will be attempted against each
prefixstable IPv6Token variable provided in the configuration; if
a received prefix does not match any of the provided addresses,
then the EUI-64 algorithm will be used to form an interface
identifier for that prefix. This mode is also SLAAC, but with a
potentially stable interface identifier which does not directly
map to the interface's hardware address. Note that the
prefixstable algorithm includes both the interface's name and MAC
address in the hash used to compute the interface identifier, so
if either of those are changed the resulting interface identifier
(and address) will change, even if the prefix received in the RA
message has not changed. Note that if multiple prefixstable
IPv6Token variables are supplied with addresses that match a
prefix received in an RA message, only the first one will be used
to generate addresses.
LLMNR=
Takes a boolean or "resolve". When true, enables Link-Local
Multicast Name Resolution[2] on the link. When set to "resolve",
only resolution is enabled, but not host registration and
announcement. Defaults to true. This setting is read by
systemd-resolved.service(8).
MulticastDNS=
Takes a boolean or "resolve". When true, enables Multicast DNS[3]
support on the link. When set to "resolve", only resolution is
enabled, but not host or service registration and announcement.
Defaults to false. This setting is read by
systemd-resolved.service(8).
DNSOverTLS=
Takes a boolean or "opportunistic". When true, enables
DNS-over-TLS[4] support on the link. When set to "opportunistic",
compatibility with non-DNS-over-TLS servers is increased, by
automatically turning off DNS-over-TLS servers in this case. This
option defines a per-interface setting for resolved.conf(5)'s
global DNSOverTLS= option. Defaults to false. This setting is
read by systemd-resolved.service(8).
DNSSEC=
Takes a boolean or "allow-downgrade". When true, enables
DNSSEC[5] DNS validation support on the link. When set to
"allow-downgrade", compatibility with non-DNSSEC capable networks
is increased, by automatically turning off DNSSEC in this case.
This option defines a per-interface setting for
resolved.conf(5)'s global DNSSEC= option. Defaults to false. This
setting is read by systemd-resolved.service(8).
DNSSECNegativeTrustAnchors=
A space-separated list of DNSSEC negative trust anchor domains.
If specified and DNSSEC is enabled, look-ups done via the
interface's DNS server will be subject to the list of negative
trust anchors, and not require authentication for the specified
domains, or anything below it. Use this to disable DNSSEC
authentication for specific private domains, that cannot be
proven valid using the Internet DNS hierarchy. Defaults to the
empty list. This setting is read by systemd-resolved.service(8).
LLDP=
Controls support for Ethernet LLDP packet reception. LLDP is a
link-layer protocol commonly implemented on professional routers
and bridges which announces which physical port a system is
connected to, as well as other related data. Accepts a boolean or
the special value "routers-only". When true, incoming LLDP
packets are accepted and a database of all LLDP neighbors
maintained. If "routers-only" is set only LLDP data of various
types of routers is collected and LLDP data about other types of
devices ignored (such as stations, telephones and others). If
false, LLDP reception is disabled. Defaults to "routers-only".
Use networkctl(1) to query the collected neighbor data. LLDP is
only available on Ethernet links. See EmitLLDP= below for
enabling LLDP packet emission from the local system.
EmitLLDP=
Controls support for Ethernet LLDP packet emission. Accepts a
boolean parameter or the special values "nearest-bridge",
"non-tpmr-bridge" and "customer-bridge". Defaults to false, which
turns off LLDP packet emission. If not false, a short LLDP packet
with information about the local system is sent out in regular
intervals on the link. The LLDP packet will contain information
about the local hostname, the local machine ID (as stored in
machine-id(5)) and the local interface name, as well as the
pretty hostname of the system (as set in machine-info(5)). LLDP
emission is only available on Ethernet links. Note that this
setting passes data suitable for identification of host to the
network and should thus not be enabled on untrusted networks,
where such identification data should not be made available. Use
this option to permit other systems to identify on which
interfaces they are connected to this system. The three special
values control propagation of the LLDP packets. The
"nearest-bridge" setting permits propagation only to the nearest
connected bridge, "non-tpmr-bridge" permits propagation across
Two-Port MAC Relays, but not any other bridges, and
"customer-bridge" permits propagation until a customer bridge is
reached. For details about these concepts, see IEEE
802.1AB-2016[6]. Note that configuring this setting to true is
equivalent to "nearest-bridge", the recommended and most
restricted level of propagation. See LLDP= above for an option to
enable LLDP reception.
BindCarrier=
A link name or a list of link names. When set, controls the
behavior of the current link. When all links in the list are in
an operational down state, the current link is brought down. When
at least one link has carrier, the current interface is brought
up.
Address=
A static IPv4 or IPv6 address and its prefix length, separated by
a "/" character. Specify this key more than once to configure
several addresses. The format of the address must be as described
in inet_pton(3). This is a short-hand for an [Address] section
only containing an Address key (see below). This option may be
specified more than once.
If the specified address is "0.0.0.0" (for IPv4) or "::" (for
IPv6), a new address range of the requested size is automatically
allocated from a system-wide pool of unused ranges. Note that the
prefix length must be equal or larger than 8 for IPv4, and 64 for
IPv6. The allocated range is checked against all current network
interfaces and all known network configuration files to avoid
address range conflicts. The default system-wide pool consists of
192.168.0.0/16, 172.16.0.0/12 and 10.0.0.0/8 for IPv4, and
fd00::/8 for IPv6. This functionality is useful to manage a large
number of dynamically created network interfaces with the same
network configuration and automatic address range assignment.
Gateway=
The gateway address, which must be in the format described in
inet_pton(3). This is a short-hand for a [Route] section only
containing a Gateway key. This option may be specified more than
once.
DNS=
A DNS server address, which must be in the format described in
inet_pton(3). This option may be specified more than once. 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.service(8).
Domains=
A whitespace-separated list of domains which should be resolved
using the DNS servers on this link. Each item in the list should
be a domain name, optionally prefixed with a tilde ("~"). The
domains with the prefix are called "routing-only domains". The
domains without the prefix are called "search domains" and are
first used as search suffixes for extending single-label
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.service(8). "Search
domains" correspond to the domain and search entries in
resolv.conf(5). Domain name routing has no equivalent in the
traditional glibc API, which has no concept of domain name
servers limited to a specific link.
DNSDefaultRoute=
Takes a boolean argument. If true, this link's configured DNS
servers are used for resolving domain names that do not match any
link's configured Domains= setting. If false, this link's
configured DNS servers are never used for such domains, and are
exclusively used for resolving names that match at least one of
the domains configured on this link. If not specified defaults to
an automatic mode: queries not matching any link's configured
domains will be routed to this link if it has no routing-only
domains configured.
NTP=
An NTP server address (either an IP address, or a hostname). This
option may be specified more than once. This setting is read by
systemd-timesyncd.service(8).
IPForward=
Configures IP packet forwarding for the system. If enabled,
incoming packets on any network interface will be forwarded to
any other interfaces according to the routing table. Takes a
boolean, or the values "ipv4" or "ipv6", which only enable IP
packet forwarding for the specified address family. This controls
the net.ipv4.ip_forward and net.ipv6.conf.all.forwarding sysctl
options of the network interface (see ip-sysctl.txt[7] for
details about sysctl options). Defaults to "no".
Note: this setting controls a global kernel option, and does so
one way only: if a network that has this setting enabled is set
up the global setting is turned on. However, it is never turned
off again, even after all networks with this setting enabled are
shut down again.
To allow IP packet forwarding only between specific network
interfaces use a firewall.
IPMasquerade=
Configures IP masquerading for the network interface. If enabled,
packets forwarded from the network interface will be appear as
coming from the local host. Takes a boolean argument. Implies
IPForward=ipv4. Defaults to "no".
IPv6PrivacyExtensions=
Configures use of stateless temporary addresses that change over
time (see RFC 4941[8], Privacy Extensions for Stateless Address
Autoconfiguration in IPv6). Takes a boolean or the special values
"prefer-public" and "kernel". When true, enables the privacy
extensions and prefers temporary addresses over public addresses.
When "prefer-public", enables the privacy extensions, but prefers
public addresses over temporary addresses. When false, the
privacy extensions remain disabled. When "kernel", the kernel's
default setting will be left in place. Defaults to "no".
IPv6AcceptRA=
Takes a boolean. Controls IPv6 Router Advertisement (RA)
reception support for the interface. If true, RAs are accepted;
if false, RAs are ignored. When RAs are accepted, they may
trigger the start of the DHCPv6 client if the relevant flags are
set in the RA data, or if no routers are found on the link. The
default is to disable RA reception for bridge devices or when IP
forwarding is enabled, and to enable it otherwise. Cannot be
enabled on bond devices and when link local addressing is
disabled.
Further settings for the IPv6 RA support may be configured in the
[IPv6AcceptRA] section, see below.
Also see ip-sysctl.txt[7] in the kernel documentation regarding
"accept_ra", but note that systemd's setting of 1 (i.e. true)
corresponds to kernel's setting of 2.
Note that kernel's implementation of the IPv6 RA protocol is
always disabled, regardless of this setting. If this option is
enabled, a userspace implementation of the IPv6 RA protocol is
used, and the kernel's own implementation remains disabled, since
systemd-networkd needs to know all details supplied in the
advertisements, and these are not available from the kernel if
the kernel's own implementation is used.
IPv6DuplicateAddressDetection=
Configures the amount of IPv6 Duplicate Address Detection (DAD)
probes to send. When unset, the kernel's default will be used.
IPv6HopLimit=
Configures IPv6 Hop Limit. For each router that forwards the
packet, the hop limit is decremented by 1. When the hop limit
field reaches zero, the packet is discarded. When unset, the
kernel's default will be used.
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[9]. When unset, the kernel's
default will be used.
IPv6ProxyNDP=
Takes a boolean. Configures proxy NDP for IPv6. Proxy NDP
(Neighbor Discovery Protocol) is a technique for IPv6 to allow
routing of addresses to a different destination when peers expect
them to be present on a certain physical link. In this case a
router answers Neighbour Advertisement messages intended for
another machine by offering its own MAC address as destination.
Unlike proxy ARP for IPv4, it is not enabled globally, but will
only send Neighbour Advertisement messages for addresses in the
IPv6 neighbor proxy table, which can also be shown by ip -6
neighbour show proxy. systemd-networkd will control the
per-interface `proxy_ndp` switch for each configured interface
depending on this option. When unset, the kernel's default will
be used.
IPv6ProxyNDPAddress=
An IPv6 address, for which Neighbour Advertisement messages will
be proxied. This option may be specified more than once.
systemd-networkd will add the IPv6ProxyNDPAddress= entries to the
kernel's IPv6 neighbor proxy table. This option implies
IPv6ProxyNDP=yes but has no effect if IPv6ProxyNDP has been set
to false. When unset, the kernel's default will be used.
IPv6PrefixDelegation=
Whether to enable or disable Router Advertisement sending on a
link. Allowed values are "static" which distributes prefixes as
defined in the [IPv6PrefixDelegation] and any [IPv6Prefix]
sections, "dhcpv6" which requests prefixes using a DHCPv6 client
configured for another link and any values configured in the
[IPv6PrefixDelegation] section while ignoring all static prefix
configuration sections, "yes" which uses both static
configuration and DHCPv6, and "false" which turns off IPv6 prefix
delegation altogether. Defaults to "false". See the
[IPv6PrefixDelegation] and the [IPv6Prefix] sections for more
configuration options.
IPv6MTUBytes=
Configures IPv6 maximum transmission unit (MTU). An integer
greater than or equal to 1280 bytes. When unset, the kernel's
default will be used.
Bridge=
The name of the bridge to add the link to. See systemd.netdev(5).
Bond=
The name of the bond to add the link to. See systemd.netdev(5).
VRF=
The name of the VRF to add the link to. See systemd.netdev(5).
VLAN=
The name of a VLAN to create on the link. See systemd.netdev(5).
This option may be specified more than once.
IPVLAN=
The name of a IPVLAN to create on the link. See
systemd.netdev(5). This option may be specified more than once.
MACVLAN=
The name of a MACVLAN to create on the link. See
systemd.netdev(5). This option may be specified more than once.
VXLAN=
The name of a VXLAN to create on the link. See systemd.netdev(5).
This option may be specified more than once.
Tunnel=
The name of a Tunnel to create on the link. See
systemd.netdev(5). This option may be specified more than once.
MACsec=
The name of a MACsec device to create on the link. See
systemd.netdev(5). This option may be specified more than once.
ActiveSlave=
Takes a boolean. Specifies the new active slave. The
"ActiveSlave=" option is only valid for following modes:
"active-backup", "balance-alb" and "balance-tlb". Defaults to
false.
PrimarySlave=
Takes a boolean. Specifies which slave is the primary device. The
specified device will always be the active slave while it is
available. Only when the primary is off-line will alternate
devices be used. This is useful when one slave is preferred over
another, e.g. when one slave has higher throughput than another.
The "PrimarySlave=" option is only valid for following modes:
"active-backup", "balance-alb" and "balance-tlb". Defaults to
false.
ConfigureWithoutCarrier=
Takes a boolean. Allows networkd to configure a specific link
even if it has no carrier. Defaults to false. If
IgnoreCarrierLoss= 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
ConfigureWithoutCarrier= is used.
Xfrm=
The name of the xfrm to create on the link. See
systemd.netdev(5). This option may be specified more than once.
KeepConfiguration=
Takes a boolean or one of "static", "dhcp-on-stop", "dhcp". When
"static", systemd-networkd will not drop static addresses and
routes on starting up process. When set to "dhcp-on-stop",
systemd-networkd will not drop addresses and routes on stopping
the daemon. When "dhcp", the addresses and routes provided by a
DHCP server will never be dropped even if the DHCP lease expires.
This is contrary to the DHCP specification, but may be the best
choice if, e.g., the root filesystem relies on this connection.
The setting "dhcp" implies "dhcp-on-stop", and "yes" implies
"dhcp" and "static". Defaults to "no".
An [Address] section accepts the following keys. Specify several
[Address] sections to configure several addresses.
Address=
As in the [Network] section. This key is mandatory. Each
[Address] section can contain one Address= setting.
Peer=
The peer address in a point-to-point connection. Accepts the same
format as the Address= key.
Broadcast=
The broadcast address, which must be in the format described in
inet_pton(3). This key only applies to IPv4 addresses. If it is
not given, it is derived from the Address= key.
Label=
An address label.
PreferredLifetime=
Allows the default "preferred lifetime" of the address to be
overridden. Only three settings are accepted: "forever" or
"infinity" which is the default and means that the address never
expires, and "0" which means that the address is considered
immediately "expired" and will not be used, unless explicitly
requested. A setting of PreferredLifetime=0 is useful for
addresses which are added to be used only by a specific
application, which is then configured to use them explicitly.
Scope=
The scope of the address, which can be "global", "link" or "host"
or an unsigned integer in the range 0—255. Defaults to "global".
HomeAddress=
Takes a boolean. Designates this address the "home address" as
defined in RFC 6275[10]. Supported only on IPv6. Defaults to
false.
DuplicateAddressDetection=
Takes one of "ipv4", "ipv6", "both", "none". When "ipv4",
performs IPv4 Duplicate Address Detection. See RFC 5224[11]. When
"ipv6", performs IPv6 Duplicate Address Detection. See RFC
4862[12]. Defaults to "ipv6".
ManageTemporaryAddress=
Takes a boolean. If true the kernel manage temporary addresses
created from this one as template on behalf of Privacy Extensions
RFC 3041[13]. For this to become active, the use_tempaddr sysctl
setting has to be set to a value greater than zero. The given
address needs to have a prefix length of 64. This flag allows
using privacy extensions in a manually configured network, just
like if stateless auto-configuration was active. Defaults to
false.
AddPrefixRoute=
Takes a boolean. When true, the prefix route for the address is
automatically added. Defaults to true.
AutoJoin=
Takes a boolean. Joining multicast group on ethernet level via ip
maddr command would not work if we have an Ethernet switch that
does IGMP snooping since the switch would not replicate multicast
packets on ports that did not have IGMP reports for the multicast
addresses. Linux vxlan interfaces created via ip link add vxlan
or networkd's netdev kind vxlan have the group option that
enables then to do the required join. By extending ip address
command with option "autojoin" we can get similar functionality
for openvswitch (OVS) vxlan interfaces as well as other tunneling
mechanisms that need to receive multicast traffic. Defaults to
"no".
A [Neighbor] section accepts the following keys. The neighbor section
adds a permanent, static entry to the neighbor table (IPv6) or ARP
table (IPv4) for the given hardware address on the links matched for
the network. Specify several [Neighbor] sections to configure several
static neighbors.
Address=
The IP address of the neighbor.
LinkLayerAddress=
The link layer address (MAC address or IP address) of the
neighbor.
An [IPv6AddressLabel] section accepts the following keys. Specify
several [IPv6AddressLabel] sections to configure several address
labels. IPv6 address labels are used for address selection. See RFC
3484[14]. Precedence is managed by userspace, and only the label
itself is stored in the kernel
Label=
The label for the prefix, an unsigned integer 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.
An [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.
The [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.
The [Route] section accepts the following keys. Specify several
[Route] sections to configure several routes.
Gateway=
Takes the gateway address or special value "_dhcp". If "_dhcp",
then the gateway address provided by DHCP (or in the IPv6 case,
provided by IPv6 RA) is used.
GatewayOnLink=
Takes a boolean. If set to true, the kernel does not have to
check if the gateway is reachable directly by the current machine
(i.e., the kernel does not need to check if the gateway is
attached to the local network), so that we can insert the route
in the kernel table without it being complained about. Defaults
to "no".
Destination=
The destination prefix of the route. Possibly followed by a slash
and the prefix length. If omitted, a full-length host route is
assumed.
Source=
The source prefix of the route. Possibly followed by a slash and
the prefix length. If omitted, a full-length host route is
assumed.
Metric=
The metric of the route (an unsigned integer).
IPv6Preference=
Specifies the route preference as defined in RFC 4191[15] for
Router Discovery messages. Which can be one of "low" the route
has a lowest priority, "medium" the route has a default priority
or "high" the route has a highest priority.
Scope=
The scope of the route, which can be "global", "site", "link",
"host", or "nowhere". For IPv4 route, defaults to "host" if Type=
is "local" or "nat", and "link" if Type= is "broadcast",
"multicast", or "anycast". In other cases, defaults to "global".
PreferredSource=
The preferred source address of the route. The address must be in
the format described in inet_pton(3).
Table=
The table identifier for the route. Takes "default", "main",
"local" or a number between 1 and 4294967295. The table can be
retrieved using ip route show table num. If unset and Type= is
"local", "broadcast", "anycast", or "nat", then "local" is used.
In other cases, defaults to "main".
Protocol=
The protocol identifier for the route. Takes a number between 0
and 255 or the special values "kernel", "boot", "static", "ra"
and "dhcp". Defaults to "static".
Type=
Specifies the type for the route. Takes one of "unicast",
"local", "broadcast", "anycast", "multicast", "blackhole",
"unreachable", "prohibit", "throw", "nat", and "xresolve". If
"unicast", a regular route is defined, i.e. a route indicating
the path to take to a destination network address. If
"blackhole", packets to the defined route are discarded silently.
If "unreachable", packets to the defined route are discarded and
the ICMP message "Host Unreachable" is generated. If "prohibit",
packets to the defined route are discarded and the ICMP message
"Communication Administratively Prohibited" is generated. If
"throw", route lookup in the current routing table will fail and
the route selection process will return to Routing Policy
Database (RPDB). Defaults to "unicast".
InitialCongestionWindow=
The TCP initial congestion window is used during the start of a
TCP connection. During the start of a TCP session, when a client
requests a resource, the server's initial congestion window
determines how many data bytes will be sent during the initial
burst of data. Takes a size in bytes between 1 and 4294967295
(2^32 - 1). The usual suffixes K, M, G are supported and are
understood to the base of 1024. When unset, the kernel's default
will be used.
InitialAdvertisedReceiveWindow=
The TCP initial advertised receive window is the amount of
receive data (in bytes) that can initially be buffered at one
time on a connection. The sending host can send only that amount
of data before waiting for an acknowledgment and window update
from the receiving host. Takes a size in bytes between 1 and
4294967295 (2^32 - 1). The usual suffixes K, M, G are supported
and are understood to the base of 1024. When unset, the kernel's
default will be used.
QuickAck=
Takes a boolean. When true enables TCP quick ack mode for the
route. When unset, the kernel's default will be used.
FastOpenNoCookie=
Takes a boolean. When true enables TCP fastopen without a cookie
on a per-route basis. When unset, the kernel's default will be
used.
TTLPropagate=
Takes a boolean. When true enables TTL propagation at Label
Switched Path (LSP) egress. When unset, the kernel's default will
be used.
MTUBytes=
The maximum transmission unit in bytes to set for the route. The
usual suffixes K, M, G, are supported and are understood to the
base of 1024.
Note that if IPv6 is enabled on the interface, and the MTU is
chosen below 1280 (the minimum MTU for IPv6) it will
automatically be increased to this value.
IPServiceType=
Takes string; "CS6" or "CS4". Used to set IP service type to CS6
(network control) or CS4 (Realtime). Defaults to CS6.
MultiPathRoute=address[@name] [weight]
Configures multipath route. Multipath routing is the technique of
using multiple alternative paths through a network. Takes gateway
address. Optionally, takes a network interface name or index
separated with "@", and a weight in 1..256 for this multipath
route separated with whitespace. This setting can be specified
multiple times. If an empty string is assigned, then the all
previous assignments are cleared.
The [DHCPv4] section configures the DHCPv4 client, if it is enabled
with the DHCP= setting described above:
UseDNS=
When true (the default), the DNS servers received from the DHCP
server will be used and take precedence over any statically
configured ones.
This corresponds to the nameserver option in resolv.conf(5).
RoutesToDNS=
When true, the routes to the DNS servers received from the DHCP
server will be configured. When UseDNS= is disabled, this setting
is ignored. Defaults to false.
UseNTP=
When true (the default), the NTP servers received from the DHCP
server will be used by systemd-timesyncd.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[16] (Anonymity Profiles for DHCP
Clients) to minimize disclosure of identifying information.
Defaults to false.
This option should only be set to true when MACAddressPolicy= is
set to "random" (see systemd.link(5)).
Note that this configuration will overwrite others. In concrete,
the following variables will be ignored: SendHostname=,
ClientIdentifier=, UseRoutes=, UseMTU=, VendorClassIdentifier=,
UseTimezone=.
With this option enabled DHCP requests will mimic those generated
by Microsoft Windows, in order to reduce the ability to
fingerprint and recognize installations. This means DHCP request
sizes will grow and lease data will be more comprehensive than
normally, though most of the requested data is not actually used.
SendHostname=
When true (the default), the machine's hostname will be sent to
the DHCP server. Note that the machine's hostname must consist
only of 7-bit ASCII lower-case characters and no spaces or dots,
and be formatted as a valid DNS domain name. Otherwise, the
hostname is not sent even if this is set to true.
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[17].
UseHostname=
When true (the default), the hostname received from the DHCP
server will be set as the transient hostname of the system.
Hostname=
Use this value for the hostname which is sent to the DHCP server,
instead of machine's hostname. Note that the specified hostname
must consist only of 7-bit ASCII lower-case characters and no
spaces or dots, and be formatted as a valid DNS domain name.
UseDomains=
Takes a boolean, or the special value "route". When true, the
domain name received from the DHCP server will be used as DNS
search domain over this link, similar to the effect of the
Domains= setting. If set to "route", the domain name received
from the DHCP server will be used for routing DNS queries only,
but not for searching, similar to the effect of the Domains=
setting when the argument is prefixed with "~". Defaults to
false.
It is recommended to enable this option only on trusted networks,
as setting this affects resolution of all 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 domain option
in resolv.conf(5).
UseRoutes=
When true (the default), the static routes will be requested from
the DHCP server and added to the routing table with a metric of
1024, and a scope of "global", "link" or "host", depending on the
route's destination and gateway. If the destination is on the
local host, e.g., 127.x.x.x, or the same as the link's own
address, the scope will be set to "host". Otherwise if the
gateway is null (a direct route), a "link" scope will be used.
For anything else, scope defaults to "global".
UseGateway=
When true, the gateway will be requested from the DHCP server and
added to the routing table with a metric of 1024, and a scope of
"link". When unset, the value specified with UseRoutes= is used.
UseTimezone=
When true, the timezone received from the DHCP server will be set
as timezone of the local system. Defaults to "no".
ClientIdentifier=
The DHCPv4 client identifier to use. Takes one of "mac", "duid"
or "duid-only". If set to "mac", the MAC address of the link is
used. If set to "duid", an RFC4361-compliant Client ID, which is
the combination of IAID and DUID (see below), is used. If set to
"duid-only", only DUID is used, this may not be RFC compliant,
but some setups may require to use this. Defaults to "duid".
VendorClassIdentifier=
The vendor class identifier used to identify vendor type and
configuration.
UserClass=
A DHCPv4 client can use UserClass option to identify the type or
category of user or applications it represents. The information
contained in this option is a string that represents the user
class of which the client is a member. Each class sets an
identifying string of information to be used by the DHCP service
to classify clients. Takes a whitespace-separated list of
strings.
MaxAttempts=
Specifies how many times the DHCPv4 client configuration should
be attempted. Takes a number or "infinity". Defaults to
"infinity". Note that the time between retries is increased
exponentially, so the network will not be overloaded even if this
number is high.
DUIDType=
Override the global DUIDType setting for this network. See
networkd.conf(5) for a description of possible values.
DUIDRawData=
Override the global DUIDRawData setting for this network. See
networkd.conf(5) for a description of possible values.
IAID=
The DHCP Identity Association Identifier (IAID) for the
interface, a 32-bit unsigned integer.
RequestBroadcast=
Request the server to use broadcast messages before the IP
address has been configured. This is necessary for devices that
cannot receive RAW packets, or that cannot receive packets at all
before an IP address has been configured. On the other hand, this
must not be enabled on networks where broadcasts are filtered
out.
RouteMetric=
Set the routing metric for routes specified by the DHCP server.
Defaults to 1024.
RouteTable=num
The table identifier for DHCP routes (a number between 1 and
4294967295, or 0 to unset). The table can be retrieved using ip
route show table num.
When used in combination with VRF=, the VRF's routing table is
used 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[11]. 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[18]. 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[18]. This
setting can be specified multiple times. If an empty string is
specified, then all options specified earlier are cleared.
Defaults to unset.
The [DHCPv6] section configures the DHCPv6 client, if it is enabled
with the DHCP= setting described above, or invoked by the IPv6 Router
Advertisement:
UseDNS=, UseNTP=
As in the [DHCPv4] section.
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[19] 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[17].
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[18]. 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[20], 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[18]. 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.
The [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[21], 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.
The [IPv6AcceptRA] section configures the IPv6 Router Advertisement
(RA) client, if it is enabled with the IPv6AcceptRA= setting
described above:
UseDNS=
When true (the default), the DNS servers received in the Router
Advertisement will be used and take precedence over any
statically configured ones.
This corresponds to the nameserver option in resolv.conf(5).
UseDomains=
Takes a boolean, or the special value "route". When true, the
domain name received via IPv6 Router Advertisement (RA) will be
used as DNS search domain over this link, similar to the effect
of the Domains= setting. If set to "route", the domain name
received via IPv6 RA will be used for routing DNS queries only,
but not for searching, similar to the effect of the Domains=
setting when the argument is prefixed with "~". Defaults to
false.
It is recommended to enable this option only on trusted networks,
as setting this affects resolution of all 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 domain option
in resolv.conf(5).
RouteTable=num
The table identifier for the routes received in the Router
Advertisement (a number between 1 and 4294967295, or 0 to unset).
The table can be retrieved using ip route show table num.
UseAutonomousPrefix=
When true (the default), the autonomous prefix received in the
Router Advertisement will be used and take precedence over any
statically configured ones.
UseOnLinkPrefix=
When true (the default), the onlink prefix received in the Router
Advertisement will be used and take precedence over any
statically configured ones.
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.
The [DHCPServer] section contains settings for the DHCP server, if
enabled via the DHCPServer= option described above:
PoolOffset=, PoolSize=
Configures the pool of addresses to hand out. The pool is a
contiguous sequence of IP addresses in the subnet configured for
the server address, which does not include the subnet nor the
broadcast address. PoolOffset= takes the offset of the pool from
the start of subnet, or zero to use the default value. PoolSize=
takes the number of IP addresses in the pool or zero to use the
default value. By default, the pool starts at the first address
after the subnet address and takes up the rest of the subnet,
excluding the broadcast address. If the pool includes the server
address (the default), this is reserved and not handed out to
clients.
DefaultLeaseTimeSec=, MaxLeaseTimeSec=
Control the default and maximum DHCP lease time to pass to
clients. These settings take time values in seconds or another
common time unit, depending on the suffix. The default lease time
is used for clients that did not ask for a specific lease time.
If a client asks for a lease time longer than the maximum lease
time, it is automatically shortened to the specified time. The
default lease time defaults to 1h, the maximum lease time to 12h.
Shorter lease times are beneficial if the configuration data in
DHCP leases changes frequently and clients shall learn the new
settings with shorter latencies. Longer lease times reduce the
generated DHCP network traffic.
EmitDNS=, DNS=
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[18]. 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[18]. This setting can be specified multiple
times. If an empty string is specified, then all options
specified earlier are cleared. Defaults to unset.
The [IPv6PrefixDelegation] section contains settings for sending IPv6
Router Advertisements and whether to act as a router, if enabled via
the IPv6PrefixDelegation= option described above. IPv6 network
prefixes are defined with one or more [IPv6Prefix] sections.
Managed=, OtherInformation=
Takes a boolean. Controls whether a DHCPv6 server is used to
acquire IPv6 addresses on the network link when Managed= is set
to "true" or if only additional network information can be
obtained via DHCPv6 for the network link when OtherInformation=
is set to "true". Both settings default to "false", which means
that a DHCPv6 server is not being used.
RouterLifetimeSec=
Takes a timespan. Configures the IPv6 router lifetime in seconds.
If set, this host also announces itself in Router Advertisements
as an IPv6 router for the network link. When unset, the host is
not acting as a router.
RouterPreference=
Configures IPv6 router preference if RouterLifetimeSec= is
non-zero. Valid values are "high", "medium" and "low", with
"normal" and "default" added as synonyms for "medium" just to
make configuration easier. See RFC 4191[15] for details. Defaults
to "medium".
EmitDNS=, DNS=
DNS= specifies a list of recursive DNS server IPv6 addresses that
are distributed via Router Advertisement messages when EmitDNS=
is true. DNS= also takes special value "_link_local"; in that
case the IPv6 link local address is distributed. If DNS= is
empty, DNS servers are read from the [Network] section. If the
[Network] section does not contain any DNS servers either, DNS
servers from the uplink with the highest priority default route
are used. When EmitDNS= is false, no DNS server information is
sent in Router Advertisement messages. EmitDNS= defaults to
true.
EmitDomains=, Domains=
A list of DNS search domains distributed via Router Advertisement
messages when EmitDomains= is true. If Domains= is empty, DNS
search domains are read from the [Network] section. If the
[Network] section does not contain any DNS search domains either,
DNS search domains from the uplink with the highest priority
default route are used. When EmitDomains= is false, no DNS search
domain information is sent in Router Advertisement messages.
EmitDomains= defaults to true.
DNSLifetimeSec=
Lifetime in seconds for the DNS server addresses listed in DNS=
and search domains listed in Domains=.
One or more [IPv6Prefix] sections contain the IPv6 prefixes that are
announced via Router Advertisements. See RFC 4861[22] 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.
One or more [IPv6RoutePrefix] sections contain the IPv6 prefix routes
that are announced via Router Advertisements. See RFC 4191[15] for
further details.
Route=
The IPv6 route that is to be distributed to hosts. Similarly to
configuring static IPv6 routes, the setting is configured as an
IPv6 prefix routes and its prefix route length, separated by a
"/" character. Use multiple [IPv6PrefixRoutes] sections to
configure multiple IPv6 prefix routes.
LifetimeSec=
Lifetime for the route prefix measured in seconds. LifetimeSec=
defaults to 604800 seconds (one week).
The [Bridge] section accepts the following keys:
UnicastFlood=
Takes a boolean. Controls whether the bridge should flood traffic
for which an FDB entry is missing and the destination is unknown
through this port. When unset, the kernel's default will be used.
MulticastFlood=
Takes a boolean. Controls whether the bridge should flood traffic
for which an MDB entry is missing and the destination is unknown
through this port. When unset, the kernel's default will be used.
MulticastToUnicast=
Takes a boolean. Multicast to unicast works on top of the
multicast snooping feature of the bridge. Which means unicast
copies are only delivered to hosts which are interested in it.
When unset, the kernel's default will be used.
NeighborSuppression=
Takes a boolean. Configures whether ARP and ND neighbor
suppression is enabled for this port. When unset, the kernel's
default will be used.
Learning=
Takes a boolean. Configures whether MAC address learning is
enabled for this port. When unset, the kernel's default will be
used.
HairPin=
Takes a boolean. Configures whether traffic may be sent back out
of the port on which it was received. When this flag is false,
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.
The [BridgeFDB] section manages the forwarding database table of a
port and accepts the following keys. Specify several [BridgeFDB]
sections to configure several static MAC table entries.
MACAddress=
As in the [Network] section. This key is mandatory.
Destination=
Takes an IP address of the destination VXLAN tunnel endpoint.
VLANId=
The VLAN ID for the new static MAC table entry. If omitted, no
VLAN ID information is appended to the new static MAC table
entry.
VNI=
The VXLAN Network Identifier (or VXLAN Segment ID) to use to
connect to the remote VXLAN tunnel endpoint. Takes a number in
the range 1-16777215. Defaults to unset.
AssociatedWith=
Specifies where the address is associated with. Takes one of
"use", "self", "master" or "router". "use" means the address is
in use. User space can use this option to indicate to the kernel
that the fdb entry is in use. "self" means the address is
associated with the port drivers fdb. Usually hardware. "master"
means the address is associated with master devices fdb.
"router" means the destination address is associated with a
router. Note that it's valid if the referenced device is a VXLAN
type device and has route shortcircuit enabled. Defaults to
"self".
The [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[17] 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.
The [CAN] section manages the Controller Area Network (CAN bus) and
accepts the following keys:
BitRate=
The bitrate of CAN device in bits per second. The usual SI
prefixes (K, M) with the base of 1000 can be used here. 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.
The [QDisc] section manages the traffic control queueing discipline
(qdisc).
Parent=
Specifies the parent Queueing Discipline (qdisc). Takes one of
"clsact" or "ingress". This is mandatory.
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
The [NetworkEmulator] section manages the queueing discipline (qdisc)
of the network emulator. It can be used to configure the kernel
packet scheduler and simulate packet delay and loss for UDP or TCP
applications, or limit the bandwidth usage of a particular service to
simulate internet connections.
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
DelaySec=
Specifies the fixed amount of delay to be added to all packets
going out of the interface. Defaults to unset.
DelayJitterSec=
Specifies the chosen delay to be added to the packets outgoing to
the network interface. Defaults to unset.
PacketLimit=
Specifies the maximum number of packets the qdisc may hold queued
at a time. An unsigned integer 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.
The [TokenBucketFilter] section manages the queueing discipline
(qdisc) of token bucket filter (tbf).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
LatencySec=
Specifies the latency parameter, which specifies the maximum
amount of time a packet can sit in the Token Bucket Filter (TBF).
Defaults to unset.
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.
The [PIE] section manages the queueing discipline (qdisc) of
Proportional Integral controller-Enhanced (PIE).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the queue size in number of packets.
When this limit is reached, incoming packets are dropped. An
unsigned integer in the range 1–4294967294. Defaults to unset and
kernel's default is used.
The [StochasticFairBlue] section manages the queueing discipline
(qdisc) of stochastic fair blue (sfb).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the queue size in number of packets.
When this limit is reached, incoming packets are dropped. An
unsigned integer in the range 0–4294967294. Defaults to unset and
kernel's default is used.
The [StochasticFairnessQueueing] section manages the queueing
discipline (qdisc) of stochastic fairness queueing (sfq).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
PerturbPeriodSec=
Specifies the interval in seconds for queue algorithm
perturbation. Defaults to unset.
The [BFIFO] section manages the queueing discipline (qdisc) of Byte
limited Packet First In First Out (bfifo).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
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.
The [PFIFO] section manages the queueing discipline (qdisc) of Packet
First In First Out (pfifo).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
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.
The [PFIFOHeadDrop] section manages the queueing discipline (qdisc)
of Packet First In First Out Head Drop (pfifo_head_drop).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
PacketLimit=
As in [PFIFO] section.
The [PFIFOFast] section manages the queueing discipline (qdisc) of
Packet First In First Out Fast (pfifo_fast).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
The [CAKE] section manages the queueing discipline (qdisc) of Common
Applications Kept Enhanced (CAKE).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
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.
The [ControlledDelay] section manages the queueing discipline (qdisc)
of controlled delay (CoDel).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the queue size in number of packets.
When this limit is reached, incoming packets are dropped. An
unsigned integer 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.
The [DeficitRoundRobinScheduler] section manages the queueing
discipline (qdisc) of Deficit Round Robin Scheduler (DRR).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
The [DeficitRoundRobinSchedulerClass] section manages the traffic
control class of Deficit Round Robin Scheduler (DRR).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", or a qdisc identifier. The qdisc identifier is specified
as the major and minor numbers in hexadecimal in the range
0x1–Oxffff separated with a colon ("major:minor"). Defaults to
"root".
ClassId=
Configues the unique identifier of the class. It is specified as
the major and minor numbers in hexadecimal in the range
0x1–Oxffff separated with a colon ("major:minor"). Defaults to
unset.
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.
The [EnhancedTransmissionSelection] section manages the queueing
discipline (qdisc) of Enhanced Transmission Selection (ETS).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
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.
The [GenericRandomEarlyDetection] section manages the queueing
discipline (qdisc) of Generic Random Early Detection (GRED).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
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.
The [FairQueueingControlledDelay] section manages the queueing
discipline (qdisc) of fair queuing controlled delay (FQ-CoDel).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the real queue size. When this limit
is reached, incoming packets are dropped. Defaults to unset and
kernel's default is used.
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.
The [FairQueueing] section manages the queueing discipline (qdisc) of
fair queue traffic policing (FQ).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the real queue size. When this limit
is reached, incoming packets are dropped. Defaults to unset and
kernel's default is used.
FlowLimit=
Specifies the hard limit on the maximum number of packets queued
per flow. Defaults to unset and kernel's default is used.
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.
The [TrivialLinkEqualizer] section manages the queueing discipline
(qdisc) of trivial link equalizer (teql).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
Id=
Specifies the interface ID "N" of teql. Defaults to "0". Note
that when teql is used, currently, the module sch_teql with
max_equalizers=N+1 option must be loaded before systemd-networkd
is started.
The [HierarchyTokenBucket] section manages the queueing discipline
(qdisc) of hierarchy token bucket (htb).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
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=.
The [HierarchyTokenBucketClass] section manages the traffic control
class of hierarchy token bucket (htb).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", or a qdisc identifier. The qdisc identifier is specified
as the major and minor numbers in hexadecimal in the range
0x1–Oxffff separated with a colon ("major:minor"). Defaults to
"root".
ClassId=
Configues the unique identifier of the class. It is specified as
the major and minor numbers in hexadecimal in the range
0x1–Oxffff separated with a colon ("major:minor"). Defaults to
unset.
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.
The [HeavyHitterFilter] section manages the queueing discipline
(qdisc) of Heavy Hitter Filter (hhf).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
PacketLimit=
Specifies the hard limit on the queue size in number of packets.
When this limit is reached, incoming packets are dropped. An
unsigned integer in the range 0–4294967294. Defaults to unset and
kernel's default is used.
The [QuickFairQueueing] section manages the queueing discipline
(qdisc) of Quick Fair Queueing (QFQ).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", "clsact", "ingress" or a class identifier. The class
identifier is specified as the major and minor numbers in
hexadecimal in the range 0x1–Oxffff separated with a colon
("major:minor"). Defaults to "root".
Handle=
Configures the major number of unique identifier of the qdisc,
known as the handle. Takes a hexadecimal number in the range
0x1–0xffff. Defaults to unset.
The [QuickFairQueueingClass] section manages the traffic control
class of Quick Fair Queueing (qfq).
Parent=
Configures the parent Queueing Discipline (qdisc). Takes one of
"root", or a qdisc identifier. The qdisc identifier is specified
as the major and minor numbers in hexadecimal in the range
0x1–Oxffff separated with a colon ("major:minor"). Defaults to
"root".
ClassId=
Configues the unique identifier of the class. It is specified as
the major and minor numbers in hexadecimal in the range
0x1–Oxffff separated with a colon ("major:minor"). Defaults to
unset.
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.
The [BridgeVLAN] section manages the VLAN ID configuration of a
bridge port and accepts the following keys. Specify several
[BridgeVLAN] sections to configure several VLAN entries. The
VLANFiltering= option has to be enabled, see the [Bridge] section in
systemd.netdev(5).
VLAN=
The VLAN ID allowed on the port. This can be either a single ID
or a range M-N. VLAN IDs are valid from 1 to 4094.
EgressUntagged=
The VLAN ID specified here will be used to untag frames on
egress. Configuring EgressUntagged= implicates the use of VLAN=
above and will enable the VLAN ID for ingress as well. This can
be either a single ID or a range M-N.
PVID=
The Port VLAN ID specified here is assigned to all untagged
frames at ingress. PVID= can be used only once. Configuring
PVID= implicates the use of VLAN= above and will enable the VLAN
ID for ingress as well.
Example 1. Static network configuration
# /etc/systemd/network/50-static.network
[Match]
Name=enp2s0
[Network]
Address=192.168.0.15/24
Gateway=192.168.0.1
This brings interface "enp2s0" up with a static address. The
specified gateway will be used for a default route.
Example 2. DHCP on ethernet links
# /etc/systemd/network/80-dhcp.network
[Match]
Name=en*
[Network]
DHCP=yes
This will enable DHCPv4 and DHCPv6 on all interfaces with names
starting with "en" (i.e. ethernet interfaces).
Example 3. IPv6 Prefix Delegation
# /etc/systemd/network/55-ipv6-pd-upstream.network
[Match]
Name=enp1s0
[Network]
DHCP=ipv6
# /etc/systemd/network/56-ipv6-pd-downstream.network
[Match]
Name=enp2s0
[Network]
IPv6PrefixDelegation=dhcpv6
This will enable IPv6 PD on the interface enp1s0 as an upstream
interface where the DHCPv6 client is running and enp2s0 as a
downstream interface where the prefix is delegated to.
Example 4. A bridge with two enslaved links
# /etc/systemd/network/25-bridge-static.network
[Match]
Name=bridge0
[Network]
Address=192.168.0.15/24
Gateway=192.168.0.1
DNS=192.168.0.1
# /etc/systemd/network/25-bridge-slave-interface-1.network
[Match]
Name=enp2s0
[Network]
Bridge=bridge0
# /etc/systemd/network/25-bridge-slave-interface-2.network
[Match]
Name=wlp3s0
[Network]
Bridge=bridge0
This creates a bridge and attaches devices "enp2s0" and "wlp3s0" to
it. The bridge will have the specified static address and network
assigned, and a default route via the specified gateway will be
added. The specified DNS server will be added to the global list of
DNS resolvers.
Example 5.
# /etc/systemd/network/20-bridge-slave-interface-vlan.network
[Match]
Name=enp2s0
[Network]
Bridge=bridge0
[BridgeVLAN]
VLAN=1-32
PVID=42
EgressUntagged=42
[BridgeVLAN]
VLAN=100-200
[BridgeVLAN]
EgressUntagged=300-400
This overrides the configuration specified in the previous example
for the interface "enp2s0", and enables VLAN on that bridge port.
VLAN IDs 1-32, 42, 100-400 will be allowed. Packets tagged with VLAN
IDs 42, 300-400 will be untagged when they leave on this interface.
Untagged packets which arrive on this interface will be assigned VLAN
ID 42.
Example 6. Various tunnels
/etc/systemd/network/25-tunnels.network
[Match]
Name=ens1
[Network]
Tunnel=ipip-tun
Tunnel=sit-tun
Tunnel=gre-tun
Tunnel=vti-tun
/etc/systemd/network/25-tunnel-ipip.netdev
[NetDev]
Name=ipip-tun
Kind=ipip
/etc/systemd/network/25-tunnel-sit.netdev
[NetDev]
Name=sit-tun
Kind=sit
/etc/systemd/network/25-tunnel-gre.netdev
[NetDev]
Name=gre-tun
Kind=gre
/etc/systemd/network/25-tunnel-vti.netdev
[NetDev]
Name=vti-tun
Kind=vti
This will bring interface "ens1" up and create an IPIP tunnel, a SIT
tunnel, a GRE tunnel, and a VTI tunnel using it.
Example 7. A bond device
# /etc/systemd/network/30-bond1.network
[Match]
Name=bond1
[Network]
DHCP=ipv6
# /etc/systemd/network/30-bond1.netdev
[NetDev]
Name=bond1
Kind=bond
# /etc/systemd/network/30-bond1-dev1.network
[Match]
MACAddress=52:54:00:e9:64:41
[Network]
Bond=bond1
# /etc/systemd/network/30-bond1-dev2.network
[Match]
MACAddress=52:54:00:e9:64:42
[Network]
Bond=bond1
This will create a bond device "bond1" and enslave the two devices
with MAC addresses 52:54:00:e9:64:41 and 52:54:00:e9:64:42 to it.
IPv6 DHCP will be used to acquire an address.
Example 8. Virtual Routing and Forwarding (VRF)
Add the "bond1" interface to the VRF master interface "vrf1". This
will redirect routes generated on this interface to be within the
routing table defined during VRF creation. For kernels before 4.8
traffic won't be redirected towards the VRFs routing table unless
specific ip-rules are added.
# /etc/systemd/network/25-vrf.network
[Match]
Name=bond1
[Network]
VRF=vrf1
Example 9. MacVTap
This brings up a network interface "macvtap-test" and attaches it to
"enp0s25".
# /usr/lib/systemd/network/25-macvtap.network
[Match]
Name=enp0s25
[Network]
MACVTAP=macvtap-test
Example 10. A Xfrm interface with physical underlying device.
# /etc/systemd/network/27-xfrm.netdev
[NetDev]
Name=xfrm0
[Xfrm]
InterfaceId=7
# /etc/systemd/network/27-eth0.network
[Match]
Name=eth0
[Network]
Xfrm=xfrm0
This creates a "xfrm0" interface and binds it to the "eth0" device.
This allows hardware based ipsec offloading to the "eth0" nic. If
offloading is not needed, xfrm interfaces can be assigned to the "lo"
device.
systemd(1), systemd-networkd.service(8), systemd.link(5),
systemd.netdev(5), systemd-resolved.service(8)
1. RFC 7217
https://tools.ietf.org/html/rfc7217
2. Link-Local Multicast Name Resolution
https://tools.ietf.org/html/rfc4795
3. Multicast DNS
https://tools.ietf.org/html/rfc6762
4. DNS-over-TLS
https://tools.ietf.org/html/rfc7858
5. DNSSEC
https://tools.ietf.org/html/rfc4033
6. IEEE 802.1AB-2016
https://standards.ieee.org/findstds/standard/802.1AB-2016.html
7. ip-sysctl.txt
https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt
8. RFC 4941
https://tools.ietf.org/html/rfc4941
9. RFC 1027
https://tools.ietf.org/html/rfc1027
10. RFC 6275
https://tools.ietf.org/html/rfc6275
11. RFC 5224
https://tools.ietf.org/html/rfc5227
12. RFC 4862
https://tools.ietf.org/html/rfc4862
13. RFC 3041
https://tools.ietf.org/html/rfc3041
14. RFC 3484
https://tools.ietf.org/html/rfc3484
15. RFC 4191
https://tools.ietf.org/html/rfc4191
16. RFC 7844
https://tools.ietf.org/html/rfc7844
17. RFC 8520
https://tools.ietf.org/html/rfc8520
18. C-style escapes
https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences
19. RFC 3315
https://tools.ietf.org/html/rfc3315#section-17.2.1
20. RFC 7084
https://tools.ietf.org/html/rfc7084
21. RFC 4291
https://tools.ietf.org/html/rfc4291#section-2.5.4
22. RFC 4861
https://tools.ietf.org/html/rfc4861
This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2020-08-13. (At that
time, the date of the most recent commit that was found in the repos‐
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of the original manual page), send a mail to man-pages@man7.org
systemd 246 SYSTEMD.NETWORK(5)
Pages that refer to this page: networkctl(1) , resolvconf(1) , resolvectl(1) , dnssec-trust-anchors.d(5) , networkd.conf(5) , networkd.conf.d(5) , systemd.link(5) , systemd.negative(5) , systemd.netdev(5) , systemd.positive(5) , 30-systemd-environment-d-generator(7) , systemd.directives(7) , systemd.index(7) , systemd.syntax(7) , systemd-networkd(8) , systemd-networkd.service(8) , systemd-network-generator(8) , systemd-network-generator.service(8) , systemd-resolved(8) , systemd-resolved.service(8) , systemd-timesyncd(8) , systemd-timesyncd.service(8)