# systemd.netdev

## NAME



           systemd.netdev - Virtual Network Device configuration
    


## SYNOPSIS



           _netdev_.netdev
    


## DESCRIPTION



           A plain ini-style text file that encodes configuration about a
           virtual network device, used by systemd-networkd(8). See
           systemd.syntax(7) for a general description of the syntax.
    
           The main Virtual Network Device file must have the extension
           .netdev; other extensions are ignored. Virtual network devices are
           created as soon as **systemd-networkd** is started if possible. If a
           netdev with the specified name already exists, **systemd-networkd**
           will try to update the config if the kind of the existing netdev
           is equivalent to the requested one, otherwise (e.g. when bridge
           device foo exists but bonding device with the same name is
           configured in a .netdev file) use the existing netdev as-is rather
           than replacing with the requested netdev. Note, several settings
           (e.g. vlan ID) cannot be changed after the netdev is created. To
           change such settings, it is necessary to first remove the existing
           netdev, and then run **networkctl reload** command or restart
           **systemd-networkd**. See also networkctl(1).
    
           The .netdev files are read from the files located in the system
           network directory /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 alphanumeric order,
           regardless of the directories in which they live. However, files
           with identical filenames replace each other. It is recommended
           that each filename is prefixed with a number smaller than "70"
           (e.g.  10-vlan.netdev). Otherwise, .netdev files generated by
           systemd-network-generator.service(8) may take precedence over user
           configured files. Files in /etc/ have the highest priority, files
           in /run/ take precedence over files with the same name in
           /usr/lib/. This can be used to override a system-supplied
           configuration file with a local file if needed. 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 netdev file foo.netdev, a "drop-in" directory
           foo.netdev.d/ may exist. All files with the suffix ".conf" from
           this directory will be merged in the alphanumeric order and parsed
           after the main file itself has been 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 netdev file wherever located. (Of course, since /run/ is
           temporary and /usr/lib/ is for vendors, it is unlikely drop-ins
           should be used in either of those places.)
    


## SUPPORTED NETDEV KINDS



           The following kinds of virtual network devices may be configured
           in .netdev files:
    
           **Table 1. Supported kinds of virtual network devices**
           ┌───────────┬──────────────────────────┐
           │ **Kind** │ **Description** │
           ├───────────┼──────────────────────────┤
           │ _bond_      │ A bond device is an      │
           │           │ aggregation of all its   │
           │           │ slave devices. See **Linux** │
           │           │ **Ethernet Bonding Driver** │
           │           │ **HOWTO******[1] for details.    │
           ├───────────┼──────────────────────────┤
           │ _bridge_    │ A bridge device is a     │
           │           │ software switch, and     │
           │           │ each of its slave        │
           │           │ devices and the bridge   │
           │           │ itself are ports of the  │
           │           │ switch.                  │
           ├───────────┼──────────────────────────┤
           │ _dummy_     │ A dummy device drops all │
           │           │ packets sent to it.      │
           ├───────────┼──────────────────────────┤
           │ _gre_       │ A Level 3 GRE tunnel     │
           │           │ over IPv4. See **RFC** │
           │           │ **2784******[2] for details.     │
           │           │ Name "gre0" should not   │
           │           │ be used, as the kernel   │
           │           │ creates a device with    │
           │           │ this name when the       │
           │           │ corresponding kernel     │
           │           │ module is loaded.        │
           ├───────────┼──────────────────────────┤
           │ _gretap_    │ A Level 2 GRE tunnel     │
           │           │ over IPv4. Name          │
           │           │ "gretap0" should not be  │
           │           │ used, as the kernel      │
           │           │ creates a device with    │
           │           │ this name when the       │
           │           │ corresponding kernel     │
           │           │ module is loaded.        │
           ├───────────┼──────────────────────────┤
           │ _erspan_    │ ERSPAN mirrors traffic   │
           │           │ on one or more source    │
           │           │ ports and delivers the   │
           │           │ mirrored traffic to one  │
           │           │ or more destination      │
           │           │ ports on another switch. │
           │           │ The traffic is           │
           │           │ encapsulated in generic  │
           │           │ routing encapsulation    │
           │           │ (GRE) and is therefore   │
           │           │ routable across a layer  │
           │           │ 3 network between the    │
           │           │ source switch and the    │
           │           │ destination switch. Name │
           │           │ "erspan0" should not be  │
           │           │ used, as the kernel      │
           │           │ creates a device with    │
           │           │ this name when the       │
           │           │ corresponding kernel     │
           │           │ module is loaded.        │
           ├───────────┼──────────────────────────┤
           │ _ip6gre_    │ A Level 3 GRE tunnel     │
           │           │ over IPv6.               │
           ├───────────┼──────────────────────────┤
           │ _ip6tnl_    │ An IPv4 or IPv6 tunnel   │
           │           │ over IPv6                │
           ├───────────┼──────────────────────────┤
           │ _ip6gretap_ │ A Level 2 GRE tunnel     │
           │           │ over IPv6.               │
           ├───────────┼──────────────────────────┤
           │ _ipip_      │ An IPv4 over IPv4        │
           │           │ tunnel.                  │
           ├───────────┼──────────────────────────┤
           │ _ipvlan_    │ An IPVLAN device is a    │
           │           │ stacked device which     │
           │           │ receives packets from    │
           │           │ its underlying device    │
           │           │ based on IP address      │
           │           │ filtering.               │
           ├───────────┼──────────────────────────┤
           │ _ipvtap_    │ An IPVTAP device is a    │
           │           │ stacked device which     │
           │           │ receives packets from    │
           │           │ its underlying device    │
           │           │ based on IP address      │
           │           │ filtering and can be     │
           │           │ accessed using the tap   │
           │           │ user space interface.    │
           ├───────────┼──────────────────────────┤
           │ _macvlan_   │ A macvlan device is a    │
           │           │ stacked device which     │
           │           │ receives packets from    │
           │           │ its underlying device    │
           │           │ based on MAC address     │
           │           │ filtering.               │
           ├───────────┼──────────────────────────┤
           │ _macvtap_   │ A macvtap device is a    │
           │           │ stacked device which     │
           │           │ receives packets from    │
           │           │ its underlying device    │
           │           │ based on MAC address     │
           │           │ filtering.               │
           ├───────────┼──────────────────────────┤
           │ _sit_       │ An IPv6 over IPv4        │
           │           │ tunnel.                  │
           ├───────────┼──────────────────────────┤
           │ _tap_       │ A persistent Level 2     │
           │           │ tunnel between a network │
           │           │ device and a device      │
           │           │ node.                    │
           ├───────────┼──────────────────────────┤
           │ _tun_       │ A persistent Level 3     │
           │           │ tunnel between a network │
           │           │ device and a device      │
           │           │ node.                    │
           ├───────────┼──────────────────────────┤
           │ _veth_      │ An Ethernet tunnel       │
           │           │ between a pair of        │
           │           │ network devices.         │
           ├───────────┼──────────────────────────┤
           │ _vlan_      │ A VLAN is a stacked      │
           │           │ device which receives    │
           │           │ packets from its         │
           │           │ underlying device based  │
           │           │ on VLAN tagging. See     │
           │           │ **IEEE 802.1Q******[3] for       │
           │           │ details.                 │
           ├───────────┼──────────────────────────┤
           │ _vti_       │ An IPv4 over IPSec       │
           │           │ tunnel.                  │
           ├───────────┼──────────────────────────┤
           │ _vti6_      │ An IPv6 over IPSec       │
           │           │ tunnel.                  │
           ├───────────┼──────────────────────────┤
           │ _vxlan_     │ A virtual extensible LAN │
           │           │ (vxlan), for connecting  │
           │           │ Cloud computing          │
           │           │ deployments.             │
           ├───────────┼──────────────────────────┤
           │ _geneve_    │ A GEneric NEtwork        │
           │           │ Virtualization           │
           │           │ Encapsulation (GENEVE)   │
           │           │ netdev driver.           │
           ├───────────┼──────────────────────────┤
           │ _hsr_       │ A High-availability      │
           │           │ Seamless Redundancy      │
           │           │ (HSR) or Parallel        │
           │           │ Redundancy Protocol      │
           │           │ (PRP) interface. HSR and │
           │           │ PRP are two protocols    │
           │           │ defined by the IEC       │
           │           │ 62439-3 standard,        │
           │           │ providing seamless       │
           │           │ failover against failure │
           │           │ of any single network    │
           │           │ component.               │
           ├───────────┼──────────────────────────┤
           │ _l2tp_      │ A Layer 2 Tunneling      │
           │           │ Protocol (L2TP) is a     │
           │           │ tunneling protocol used  │
           │           │ to support virtual       │
           │           │ private networks (VPNs)  │
           │           │ or as part of the        │
           │           │ delivery of services by  │
           │           │ ISPs. It does not        │
           │           │ provide any encryption   │
           │           │ or confidentiality by    │
           │           │ itself                   │
           ├───────────┼──────────────────────────┤
           │ _macsec_    │ Media Access Control     │
           │           │ Security (MACsec) is an  │
           │           │ 802.1AE IEEE             │
           │           │ industry-standard        │
           │           │ security technology that │
           │           │ provides secure          │
           │           │ communication for all    │
           │           │ traffic on Ethernet      │
           │           │ links. MACsec provides   │
           │           │ point-to-point security  │
           │           │ on Ethernet links        │
           │           │ between directly         │
           │           │ connected nodes and is   │
           │           │ capable of identifying   │
           │           │ and preventing most      │
           │           │ security threats.        │
           ├───────────┼──────────────────────────┤
           │ _vrf_       │ A Virtual Routing and    │
           │           │ Forwarding (**VRF******[4])      │
           │           │ interface to create      │
           │           │ separate routing and     │
           │           │ forwarding domains.      │
           ├───────────┼──────────────────────────┤
           │ _vcan_      │ The virtual CAN driver   │
           │           │ (vcan). Similar to the   │
           │           │ network loopback         │
           │           │ devices, vcan offers a   │
           │           │ virtual local CAN        │
           │           │ interface.               │
           ├───────────┼──────────────────────────┤
           │ _vxcan_     │ The virtual CAN tunnel   │
           │           │ driver (vxcan). Similar  │
           │           │ to the virtual ethernet  │
           │           │ driver veth, vxcan       │
           │           │ implements a local CAN   │
           │           │ traffic tunnel between   │
           │           │ two virtual CAN network  │
           │           │ devices. When creating a │
           │           │ vxcan, two vxcan devices │
           │           │ are created as pair.     │
           │           │ When one end receives    │
           │           │ the packet it appears on │
           │           │ its pair and vice versa. │
           │           │ The vxcan can be used    │
           │           │ for cross namespace      │
           │           │ communication.           │
           ├───────────┼──────────────────────────┤
           │ _wireguard_ │ WireGuard Secure Network │
           │           │ Tunnel.                  │
           ├───────────┼──────────────────────────┤
           │ _nlmon_     │ A Netlink monitor        │
           │           │ device. Use an nlmon     │
           │           │ device when you want to  │
           │           │ monitor system Netlink   │
           │           │ messages.                │
           ├───────────┼──────────────────────────┤
           │ _fou_       │ Foo-over-UDP tunneling.  │
           ├───────────┼──────────────────────────┤
           │ _xfrm_      │ A virtual tunnel         │
           │           │ interface like vti/vti6  │
           │           │ but with several         │
           │           │ advantages.              │
           ├───────────┼──────────────────────────┤
           │ _ifb_       │ The Intermediate         │
           │           │ Functional Block (ifb)   │
           │           │ pseudo network interface │
           │           │ acts as a QoS            │
           │           │ concentrator for         │
           │           │ multiple different       │
           │           │ sources of traffic.      │
           ├───────────┼──────────────────────────┤
           │ _bareudp_   │ Bare UDP tunnels provide │
           │           │ a generic L3             │
           │           │ encapsulation support    │
           │           │ for tunnelling different │
           │           │ L3 protocols like MPLS,  │
           │           │ IP etc. inside of a UDP  │
           │           │ tunnel.                  │
           ├───────────┼──────────────────────────┤
           │ _batadv_    │ **B.A.T.M.A.N. Advanced******[5] │
           │           │ is a routing protocol    │
           │           │ for multi-hop mobile     │
           │           │ ad-hoc networks which    │
           │           │ operates on layer 2.     │
           ├───────────┼──────────────────────────┤
           │ _ipoib_     │ An IP over Infiniband    │
           │           │ subinterface.            │
           ├───────────┼──────────────────────────┤
           │ _wlan_      │ A virtual wireless       │
           │           │ network (WLAN)           │
           │           │ interface.               │
           └───────────┴──────────────────────────┘
    


## [MATCH] SECTION OPTIONS



           A virtual network device is only created if the [Match] section
           matches the current environment, or if the section is empty. The
           following keys are accepted:
    
           _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, the previously assigned value is
               cleared.
    
               Added in version 211.
    
           _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, the previously assigned value is cleared.
    
               Added in version 211.
    
           _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, the
               previously assigned value is cleared.
    
               Added in version 211.
    
           _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, the previously assigned value is cleared.
    
               Added in version 237.
    
           _Version=_
               Checks whether a software version matches a certain
               expression. See _ConditionVersion=_ in systemd.unit(5) for
               details. When prefixed with an exclamation mark ("!"), the
               result is negated. If an empty string is assigned, the
               previously assigned value is cleared.
    
               Added in version 258.
    
           _Credential=_
               Checks whether the specified credential was passed to the
               systemd-udevd.service service. See **System and Service**
               **Credentials******[6] for details. When prefixed with an exclamation
               mark ("!"), the result is negated. If an empty string is
               assigned, the previously assigned value is cleared.
    
               Added in version 252._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, the
               previously assigned value is cleared.
    
               Added in version 211.
    
           _Firmware=_
               Checks whether the system is running on a machine with the
               specified firmware. See _ConditionFirmware=_ in systemd.unit(5)
               for details. When prefixed with an exclamation mark ("!"), the
               result is negated. If an empty string is assigned, the
               previously assigned value is cleared.
    
               Added in version 249.
    


## [NETDEV] SECTION OPTIONS



           The [NetDev] section accepts the following keys:
    
           _Description=_
               A free-form description of the netdev.
    
               Added in version 215.
    
           _Name=_
               The interface name used when creating the netdev. This setting
               is compulsory.
    
               Added in version 211.
    
           _Kind=_
               The netdev kind. This setting is compulsory. See the
               "Supported netdev kinds" section for the valid keys.
    
               Added in version 211.
    
           _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. For "tun" or "tap" devices, _MTUBytes=_
               setting is not currently supported in [NetDev] section. Please
               specify it in [Link] section of corresponding
               systemd.network(5) files.
    
               Added in version 215.
    
           _MACAddress=_
               Specifies the MAC address to use for the device, or takes the
               special value "none". When "none", **systemd-networkd** does not
               request the MAC address for the device, and the kernel will
               assign a random MAC address. For "tun", "tap", or "l2tp"
               devices, the _MACAddress=_ setting in the [NetDev] section is
               not supported and will be ignored. Please specify it in the
               [Link] section of the corresponding systemd.network(5) file.
               If this option is not set, "vlan" device inherits the MAC
               address of the master interface. For other kind of netdevs, if
               this option is not set, then the MAC address is generated
               based on the interface name and the machine-id(5).
    
               Note, even if "none" is specified, **systemd-udevd** will assign
               the persistent MAC address for the device, as 99-default.link
               has _MACAddressPolicy=persistent_. So, it is also necessary to
               create a custom .link file for the device, if the MAC address
               assignment is not desired.
    
               Added in version 215.
    


## [BRIDGE] SECTION OPTIONS



           The [Bridge] section only applies for netdevs of kind "bridge",
           and accepts the following keys:
    
           _HelloTimeSec=_
               HelloTimeSec specifies the number of seconds between two hello
               packets sent out by the root bridge and the designated
               bridges. Hello packets are used to communicate information
               about the topology throughout the entire bridged local area
               network.
    
               Added in version 227.
    
           _MaxAgeSec=_
               MaxAgeSec specifies the number of seconds of maximum message
               age. If the last seen (received) hello packet is more than
               this number of seconds old, the bridge in question will start
               the takeover procedure in attempt to become the Root Bridge
               itself.
    
               Added in version 227.
    
           _ForwardDelaySec=_
               ForwardDelaySec specifies the number of seconds spent in each
               of the Listening and Learning states before the Forwarding
               state is entered.
    
               Added in version 227.
    
           _AgeingTimeSec=_
               This specifies the number of seconds a MAC Address will be
               kept in the forwarding database after having a packet received
               from this MAC Address.
    
               Added in version 232.
    
           _Priority=_
               The priority of the bridge. An integer between 0 and 65535. A
               lower value means higher priority. The bridge having the
               lowest priority will be elected as root bridge.
    
               Added in version 232.
    
           _GroupForwardMask=_
               A 16-bit bitmask represented as an integer which allows
               forwarding of link local frames with 802.1D reserved addresses
               (01:80:C2:00:00:0X). A logical AND is performed between the
               specified bitmask and the exponentiation of 2^X, the lower
               nibble of the last octet of the MAC address. For example, a
               value of 8 would allow forwarding of frames addressed to
               01:80:C2:00:00:03 (802.1X PAE).
    
               Added in version 235.
    
           _DefaultPVID=_
               This specifies the default port VLAN ID of a newly attached
               bridge port. Set this to an integer in the range 1...4094 or
               "none" to disable the PVID.
    
               Added in version 232.
    
           _MulticastQuerier=_
               Takes a boolean. This setting controls the
               IFLA_BR_MCAST_QUERIER option in the kernel. If enabled, the
               kernel will send general ICMP queries from a zero source
               address. This feature should allow faster convergence on
               startup, but it causes some multicast-aware switches to
               misbehave and disrupt forwarding of multicast packets. When
               unset, the kernel's default will be used.
    
               Added in version 230.
    
           _MulticastSnooping=_
               Takes a boolean. This setting controls the
               IFLA_BR_MCAST_SNOOPING option in the kernel. If enabled, IGMP
               snooping monitors the Internet Group Management Protocol
               (IGMP) traffic between hosts and multicast routers. When
               unset, the kernel's default will be used.
    
               Added in version 230.
    
           _VLANFiltering=_
               Takes a boolean. This setting controls the
               IFLA_BR_VLAN_FILTERING option in the kernel. If enabled, the
               bridge will be started in VLAN-filtering mode. When unset, the
               kernel's default will be used.
    
               Added in version 231.
    
           _VLANProtocol=_
               Allows setting the protocol used for VLAN filtering. Takes
               **802.1q** or, **802.1ad** , and defaults to unset and kernel's default
               is used.
    
               Added in version 246.
    
           _STP=_
               Takes a boolean. This enables the bridge's Spanning Tree
               Protocol (STP). When unset, the kernel's default will be used.
    
               Added in version 232.
    
           _MulticastIGMPVersion=_
               Allows changing bridge's multicast Internet Group Management
               Protocol (IGMP) version. Takes an integer 2 or 3. When unset,
               the kernel's default will be used.
    
               Added in version 243.
    
           _FDBMaxLearned=_
               Specifies the maximum number of learned Ethernet addresses for
               the bridge. When the limit is reached, no more addresses are
               learned. When unset, the kernel's default will be used. 0
               disables the limit.
    
               Added in version 257.
    
           _LinkLocalLearning=_
               Takes a boolean. This enables learning source addresses from
               link local frames. When unset, the kernel's default will be
               used.
    
               Added in version 258.
    


## [VLAN] SECTION OPTIONS



           The [VLAN] section only applies for netdevs of kind "vlan", and
           accepts the following key:
    
           _Id=_
               The VLAN ID to use. An integer in the range 0...4094. This
               setting is compulsory.
    
               Added in version 211.
    
           _Protocol=_
               Allows setting the protocol used for the VLAN interface. Takes
               "802.1q" or, "802.1ad", and defaults to unset and kernel's
               default is used.
    
               Added in version 248.
    
           _GVRP=_
               Takes a boolean. The Generic VLAN Registration Protocol (GVRP)
               is a protocol that allows automatic learning of VLANs on a
               network. When unset, the kernel's default will be used.
    
               Added in version 234.
    
           _MVRP=_
               Takes a boolean. Multiple VLAN Registration Protocol (MVRP)
               formerly known as GARP VLAN Registration Protocol (GVRP) is a
               standards-based Layer 2 network protocol, for automatic
               configuration of VLAN information on switches. It was defined
               in the 802.1ak amendment to 802.1Q-2005. When unset, the
               kernel's default will be used.
    
               Added in version 234.
    
           _LooseBinding=_
               Takes a boolean. The VLAN loose binding mode, in which only
               the operational state is passed from the parent to the
               associated VLANs, but the VLAN device state is not changed.
               When unset, the kernel's default will be used.
    
               Added in version 234.
    
           _ReorderHeader=_
               Takes a boolean. When enabled, the VLAN reorder header is used
               and VLAN interfaces behave like physical interfaces. When
               unset, the kernel's default will be used.
    
               Added in version 234.
    
           _EgressQOSMaps=_ , _IngressQOSMaps=_
               Defines a mapping of Linux internal packet priority
               (**SO_PRIORITY**) to VLAN header PCP field for outgoing and
               incoming frames, respectively. Takes a whitespace-separated
               list of integer pairs, where each integer must be in the range
               1...4294967294, in the format "from"-"to", e.g., "21-7 45-5".
               Note that "from" must be greater than or equal to "to". When
               unset, the kernel's default will be used.
    
               Added in version 248.
    


## [MACVLAN] SECTION OPTIONS



           The [MACVLAN] section only applies for netdevs of kind "macvlan",
           and accepts the following key:
    
           _Mode=_
               The MACVLAN mode to use. The supported options are "private",
               "vepa", "bridge", "passthru", and "source".
    
               Added in version 211.
    
           _SourceMACAddress=_
               A whitespace-separated list of remote hardware addresses
               allowed on the MACVLAN. This option only has an effect in
               source mode. 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. Defaults to unset.
    
               Added in version 246.
    
           _BroadcastMulticastQueueLength=_
               Specifies the length of the receive queue for
               broadcast/multicast packets. An unsigned integer in the range
               0...4294967294. Defaults to unset.
    
               Added in version 248.
    
           _BroadcastQueueThreshold=_
               Controls the threshold for broadcast queueing of the macvlan
               device. Takes the special value "no", or an integer in the
               range 0...2147483647. When "no" is specified, the broadcast
               queueing is disabled altogether. When an integer is specified,
               a multicast address will be queued as broadcast if the number
               of devices using the macvlan is greater than the given value.
               Defaults to unset, and the kernel default will be used.
    
               Added in version 256.
    


## [MACVTAP] SECTION OPTIONS



           The [MACVTAP] section applies for netdevs of kind "macvtap" and
           accepts the same keys as [MACVLAN].
    


## [IPVLAN] SECTION OPTIONS



           The [IPVLAN] section only applies for netdevs of kind "ipvlan",
           and accepts the following key:
    
           _Mode=_
               The IPVLAN mode to use. The supported options are "L2","L3"
               and "L3S".
    
               Added in version 219.
    
           _Flags=_
               The IPVLAN flags to use. The supported options are
               "bridge","private" and "vepa".
    
               Added in version 237.
    


## [IPVTAP] SECTION OPTIONS



           The [IPVTAP] section only applies for netdevs of kind "ipvtap" and
           accepts the same keys as [IPVLAN].
    


## [VXLAN] SECTION OPTIONS



           The [VXLAN] section only applies for netdevs of kind "vxlan", and
           accepts the following keys:
    
           _VNI=_
               The VXLAN Network Identifier (or VXLAN Segment ID). Takes a
               number in the range 1...16777215. Ignored if _External=_ is set
               to true.
    
               Added in version 243.
    
           _Remote=_
               Configures destination IP address.
    
               Added in version 233.
    
           _Local=_
               Configures local IP address. It must be an address on the
               underlying interface of the VXLAN interface, or one of the
               special values "ipv4_link_local", "ipv6_link_local", "dhcp4",
               "dhcp6", and "slaac". If one of the special values is
               specified, an address which matches the corresponding type on
               the underlying interface will be used. Defaults to unset.
    
               Added in version 233.
    
           _Group=_
               Configures VXLAN multicast group IP address. All members of a
               VXLAN must use the same multicast group address.
    
               Added in version 243.
    
           _TOS=_
               The Type Of Service byte value for a vxlan interface.
    
               Added in version 215.
    
           _TTL=_
               A fixed Time To Live N on Virtual eXtensible Local Area
               Network packets. Takes "inherit" or a number in the range
               0...255. 0 is a special value meaning inherit the inner
               protocol's TTL value.  "inherit" means that it will inherit
               the outer protocol's TTL value.
    
               Added in version 215.
    
           _MacLearning=_
               Takes a boolean. When true, enables dynamic MAC learning to
               discover remote MAC addresses.
    
               Added in version 215.
    
           _FDBAgeingSec=_
               The lifetime of Forwarding Database entry learnt by the
               kernel, in seconds.
    
               Added in version 218.
    
           _MaximumFDBEntries=_
               Configures maximum number of FDB entries.
    
               Added in version 228.
    
           _ReduceARPProxy=_
               Takes a boolean. When true, bridge-connected VXLAN tunnel
               endpoint answers ARP requests from the local bridge on behalf
               of remote **Distributed Overlay Virtual Ethernet (DOVE)******[7]
               clients. Defaults to false.
    
               Added in version 233._L2MissNotification=_
               Takes a boolean. When true, enables netlink LLADDR miss
               notifications.
    
               Added in version 218.
    
           _L3MissNotification=_
               Takes a boolean. When true, enables netlink IP address miss
               notifications.
    
               Added in version 218.
    
           _RouteShortCircuit=_
               Takes a boolean. When true, route short circuiting is turned
               on.
    
               Added in version 218.
    
           _UDPChecksum=_
               Takes a boolean. When true, transmitting UDP checksums when
               doing VXLAN/IPv4 is turned on.
    
               Added in version 220.
    
           _UDP6ZeroChecksumTx=_
               Takes a boolean. When true, sending zero checksums in
               VXLAN/IPv6 is turned on.
    
               Added in version 220.
    
           _UDP6ZeroChecksumRx=_
               Takes a boolean. When true, receiving zero checksums in
               VXLAN/IPv6 is turned on.
    
               Added in version 220.
    
           _RemoteChecksumTx=_
               Takes a boolean. When true, remote transmit checksum offload
               of VXLAN is turned on.
    
               Added in version 232.
    
           _RemoteChecksumRx=_
               Takes a boolean. When true, remote receive checksum offload in
               VXLAN is turned on.
    
               Added in version 232.
    
           _GroupPolicyExtension=_
               Takes a boolean. When true, it enables Group Policy VXLAN
               extension security label mechanism across network peers based
               on VXLAN. For details about the Group Policy VXLAN, see the
               **VXLAN Group Policy******[8] document. Defaults to false.
    
               Added in version 224._GenericProtocolExtension=_
               Takes a boolean. When true, Generic Protocol Extension extends
               the existing VXLAN protocol to provide protocol typing, OAM,
               and versioning capabilities. For details about the VXLAN GPE
               Header, see the **Generic Protocol Extension for VXLAN******[9]
               document. If destination port is not specified and Generic
               Protocol Extension is set, the default port of 4790 is used.
               Defaults to false.
    
               Added in version 243._DestinationPort=_
               Configures the default destination UDP port. If the
               destination port is not specified, the Linux kernel default
               will be used. Set to 4789 to get the IANA assigned value.
    
               Added in version 229.
    
           _PortRange=_
               Configures the source port range for the VXLAN. The kernel
               assigns the source UDP port based on the flow to help the
               receiver to do load balancing. When this option is not set,
               the normal range of local UDP ports is used.
    
               Added in version 229.
    
           _FlowLabel=_
               Specifies the flow label to use in outgoing packets. The valid
               range is 0-1048575.
    
               Added in version 234.
    
           _IPDoNotFragment=_
               Allows setting the IPv4 Do not Fragment (DF) bit in outgoing
               packets, or to inherit its value from the IPv4 inner header.
               Takes a boolean value, or "inherit". Set to "inherit" if the
               encapsulated protocol is IPv6. When unset, the kernel's
               default will be used.
    
               Added in version 243.
    
           _Independent=_
               Takes a boolean. When true, the vxlan interface is created
               without any underlying network interface. Defaults to false,
               which means that a .network file that requests this VXLAN
               interface using _VXLAN=_ is required for the VXLAN to be
               created.
    
               Added in version 247.
    
           _External=_
               Takes a boolean. When true, the vxlan interface is externally
               controlled, for example by an EVPN control plane. Defaults to
               false.
    
               Added in version 258.
    
           _VNIFilter=_
               Takes a boolean. When true, the interface is capable of
               filtering VNI filtering. Ignored if _External=_ is set to false.
               Defaults to false.
    
               Added in version 258.
    


## [GENEVE] SECTION OPTIONS



           The [GENEVE] section only applies for netdevs of kind "geneve",
           and accepts the following keys:
    
           _Id=_
               Specifies the Virtual Network Identifier (VNI) to use, a
               number between 0 and 16777215. This field is mandatory.
    
               Added in version 234.
    
           _Remote=_
               Specifies the unicast destination IP address to use in
               outgoing packets.
    
               Added in version 234.
    
           _TOS=_
               Specifies the TOS value to use in outgoing packets. Takes a
               number between 1 and 255.
    
               Added in version 234.
    
           _TTL=_
               Accepts the same values as in the [VXLAN] section, except that
               when unset or set to 0, the kernel's default will be used,
               meaning that packet TTL will be set from
               /proc/sys/net/ipv4/ip_default_ttl.
    
               Added in version 234.
    
           _UDPChecksum=_
               Takes a boolean. When true, specifies that UDP checksum is
               calculated for transmitted packets over IPv4.
    
               Added in version 234.
    
           _UDP6ZeroChecksumTx=_
               Takes a boolean. When true, skip UDP checksum calculation for
               transmitted packets over IPv6.
    
               Added in version 234.
    
           _UDP6ZeroChecksumRx=_
               Takes a boolean. When true, allows incoming UDP packets over
               IPv6 with zero checksum field.
    
               Added in version 234.
    
           _DestinationPort=_
               Specifies destination port. Defaults to 6081. If not set or
               assigned the empty string, the default port of 6081 is used.
    
               Added in version 234.
    
           _FlowLabel=_
               Specifies the flow label to use in outgoing packets.
    
               Added in version 234.
    
           _IPDoNotFragment=_
               Accepts the same key as in [VXLAN] section.
    
               Added in version 243.
    
           _InheritInnerProtocol=_
               Takes a boolean. When true, inner Layer 3 protocol is set as
               Protocol Type in the GENEVE header instead of Ethernet.
               Defaults to false.
    
               Added in version 254.
    


## [HSR] SECTION OPTIONS



           The [HSR] section only applies for netdevs of kind "hsr", and
           accepts the following keys:
    
           _Ports=_
               Specifies the underlying interfaces. This field is mandatory
               and must contain exactly two interface names separated by
               space. This option can be specified multiples times, hence the
               two cases below have the same result:
    
                   Ports=eth1 eth2
    
                   Ports=eth1
                   Ports=eth2
    
               All the previous assignments are cleared when an empty string
               is specified.
    
               Added in version 258.
    
           _Protocol=_
               Specifies the protocol used by the interface. Takes one of
               "hsr" or "prp". Defaults to "hsr".
    
               Both protocols work by sending two copies of every outgoing
               frame, one for each of the two ports. The destination node
               receives the two frames and and keeps only the first one. If a
               link fails, only one of the two frames is received. HSR uses a
               ring topology where the two outgoing frames are sent in
               opposite directions in the ring. PRP doesn't need a specific
               topology, but it requires two completely redundant networks
               attached to the two ports.
    
               Added in version 258.
    
           _Supervision=_
               Specifies the last byte of the destination MAC address of
               supervision frames. Takes a number between 0 and 255. Defaults
               to 0. Supervision frames are used by the HSR and the PRP
               protocols to monitor the integrity of the network and the
               presence of nodes. The first 5 bytes of the destination MAC
               are always 01:15:4E:00:01 while the last byte is configurable.
    
               Added in version 258.
    


## [BAREUDP] SECTION OPTIONS



           The [BareUDP] section only applies for netdevs of kind "bareudp",
           and accepts the following keys:
    
           _DestinationPort=_
               Specifies the destination UDP port (in range 1...65535). This
               is mandatory.
    
               Added in version 247.
    
           _EtherType=_
               Specifies the L3 protocol. Takes one of "ipv4", "ipv6",
               "mpls-uc" or "mpls-mc". This is mandatory.
    
               Added in version 247.
    
           _MinSourcePort=_
               Specifies the lowest value of the UDP tunnel source port (in
               range 1...65535). Defaults to unset.
    
               Added in version 257.
    


## [L2TP] SECTION OPTIONS



           The [L2TP] section only applies for netdevs of kind "l2tp", and
           accepts the following keys:
    
           _TunnelId=_
               Specifies the tunnel identifier. Takes a number in the range
               1...4294967295. The value used must match the "PeerTunnelId="
               value being used at the peer. This setting is compulsory.
    
               Added in version 242.
    
           _PeerTunnelId=_
               Specifies the peer tunnel id. Takes a number in the range
               1...4294967295. The value used must match the "TunnelId="
               value being used at the peer. This setting is compulsory.
    
               Added in version 242.
    
           _Remote=_
               Specifies the IP address of the remote peer. This setting is
               compulsory.
    
               Added in version 242.
    
           _Local=_
               Specifies the IP address of a local interface. Takes an IP
               address, or the special values "auto", "static", or "dynamic".
               Optionally a name of a local interface can be specified after
               "@", e.g.  "192.168.0.1@eth0" or "auto@eth0". When an address
               is specified, then a local or specified interface must have
               the address, and the remote address must be accessible through
               the local address. If "auto", then one of the addresses on a
               local or specified interface which is accessible to the remote
               address will be used. Similarly, if "static" or "dynamic" is
               set, then one of the static or dynamic addresses will be used.
               Defaults to "auto".
    
               Added in version 242.
    
           _EncapsulationType=_
               Specifies the encapsulation type of the tunnel. Takes one of
               "udp" or "ip".
    
               Added in version 242.
    
           _UDPSourcePort=_
               Specifies the UDP source port to be used for the tunnel. When
               UDP encapsulation is selected it is mandatory. Ignored when IP
               encapsulation is selected.
    
               Added in version 242.
    
           _UDPDestinationPort=_
               Specifies destination port. When UDP encapsulation is selected
               it is mandatory. Ignored when IP encapsulation is selected.
    
               Added in version 245.
    
           _UDPChecksum=_
               Takes a boolean. When true, specifies that UDP checksum is
               calculated for transmitted packets over IPv4.
    
               Added in version 242.
    
           _UDP6ChecksumTx=_
               Takes a boolean. When true, skip UDP checksum calculation for
               transmitted packets over IPv6.
    
               Added in version 242.
    
           _UDP6ChecksumRx=_
               Takes a boolean. When true, allows incoming UDP packets over
               IPv6 with zero checksum field.
    
               Added in version 242.
    


## [L2TPSESSION] SECTION OPTIONS



           The [L2TPSession] section only applies for netdevs of kind "l2tp",
           and accepts the following keys:
    
           _Name=_
               Specifies the name of the session. This setting is compulsory.
    
               Added in version 242.
    
           _SessionId=_
               Specifies the session identifier. Takes a number in the range
               1...4294967295. The value used must match the "SessionId="
               value being used at the peer. This setting is compulsory.
    
               Added in version 242.
    
           _PeerSessionId=_
               Specifies the peer session identifier. Takes a number in the
               range 1...4294967295. The value used must match the
               "PeerSessionId=" value being used at the peer. This setting is
               compulsory.
    
               Added in version 242.
    
           _Layer2SpecificHeader=_
               Specifies layer2specific header type of the session. One of
               "none" or "default". Defaults to "default".
    
               Added in version 242.
    


## [MACSEC] SECTION OPTIONS



           The [MACsec] section only applies for network devices of kind
           "macsec", and accepts the following keys:
    
           _Port=_
               Specifies the port to be used for the MACsec transmit channel.
               The port is used to make secure channel identifier (SCI).
               Takes a value between 1 and 65535. Defaults to unset.
    
               Added in version 243.
    
           _Encrypt=_
               Takes a boolean. When true, enable encryption. Defaults to
               unset.
    
               Added in version 243.
    


## [MACSECRECEIVECHANNEL] SECTION OPTIONS



           The [MACsecReceiveChannel] section only applies for network
           devices of kind "macsec", and accepts the following keys:
    
           _Port=_
               Specifies the port to be used for the MACsec receive channel.
               The port is used to make secure channel identifier (SCI).
               Takes a value between 1 and 65535. This option is compulsory,
               and is not set by default.
    
               Added in version 243.
    
           _MACAddress=_
               Specifies the MAC address to be used for the MACsec receive
               channel. The MAC address used to make secure channel
               identifier (SCI). This setting is compulsory, and is not set
               by default.
    
               Added in version 243.
    


## [MACSECTRANSMITASSOCIATION] SECTION OPTIONS



           The [MACsecTransmitAssociation] section only applies for network
           devices of kind "macsec", and accepts the following keys:
    
           _PacketNumber=_
               Specifies the packet number to be used for replay protection
               and the construction of the initialization vector (along with
               the secure channel identifier [SCI]). Takes a value between
               1-4,294,967,295. Defaults to unset.
    
               Added in version 243.
    
           _KeyId=_
               Specifies the identification for the key. Takes a number
               between 0-255. This option is compulsory, and is not set by
               default.
    
               Added in version 243.
    
           _Key=_
               Specifies the encryption key used in the transmission channel.
               The same key must be configured on the peer’s matching receive
               channel. This setting is compulsory, and is not set by
               default. Takes a 128-bit key encoded in a hexadecimal string,
               for example "dffafc8d7b9a43d5b9a3dfbbf6a30c16".
    
               Added in version 243.
    
           _KeyFile=_
               Takes an absolute path to a file which contains a 128-bit key
               encoded in a hexadecimal string, which will be used in the
               transmission channel. When this option is specified, _Key=_ is
               ignored. Note that the file must be readable by the user
               "systemd-network", so it should be, e.g., owned by
               "root:systemd-network" with a "0640" file mode. If the path
               refers to an **AF_UNIX** stream socket in the file system a
               connection is made to it and the key read from it.
    
               Added in version 243.
    
           _Activate=_
               Takes a boolean. If enabled, then the security association is
               activated. Defaults to unset.
    
               Added in version 243.
    
           _UseForEncoding=_
               Takes a boolean. If enabled, then the security association is
               used for encoding. Only one [MACsecTransmitAssociation]
               section can enable this option. When enabled, _Activate=yes_ is
               implied. Defaults to unset.
    
               Added in version 243.
    


## [MACSECRECEIVEASSOCIATION] SECTION OPTIONS



           The [MACsecReceiveAssociation] section only applies for network
           devices of kind "macsec", and accepts the following keys:
    
           _Port=_
               Accepts the same key as in [MACsecReceiveChannel] section.
    
               Added in version 243.
    
           _MACAddress=_
               Accepts the same key as in [MACsecReceiveChannel] section.
    
               Added in version 243.
    
           _PacketNumber=_
               Accepts the same key as in [MACsecTransmitAssociation]
               section.
    
               Added in version 243.
    
           _KeyId=_
               Accepts the same key as in [MACsecTransmitAssociation]
               section.
    
               Added in version 243.
    
           _Key=_
               Accepts the same key as in [MACsecTransmitAssociation]
               section.
    
               Added in version 243.
    
           _KeyFile=_
               Accepts the same key as in [MACsecTransmitAssociation]
               section.
    
               Added in version 243.
    
           _Activate=_
               Accepts the same key as in [MACsecTransmitAssociation]
               section.
    
               Added in version 243.
    


## [TUNNEL] SECTION OPTIONS



           The [Tunnel] section only applies for netdevs of kind "ipip",
           "sit", "gre", "gretap", "ip6gre", "ip6gretap", "vti", "vti6",
           "ip6tnl", and "erspan" and accepts the following keys:
    
           _External=_
               Takes a boolean value. When true, then the tunnel is
               externally controlled, which is also known as collect metadata
               mode, and most settings below like _Local=_ or _Remote=_ are
               ignored. This implies _Independent=_. Defaults to false.
    
               Added in version 251.
    
           _Local=_
               A static local address for tunneled packets. It must be an
               address on another interface of this host, or one of the
               special values "any", "ipv4_link_local", "ipv6_link_local",
               "dhcp4", "dhcp6", "dhcp_pd", and "slaac". If one of the
               special values except for "any" is specified, an address which
               matches the corresponding type on the underlying interface
               will be used. Defaults to "any".
    
               Added in version 215.
    
           _Remote=_
               The remote endpoint of the tunnel. Takes an IP address or the
               special value "any".
    
               Added in version 215.
    
           _TOS=_
               The Type Of Service byte value for a tunnel interface. For
               details about the TOS, see the **Type of Service in the Internet**
               **Protocol Suite******[10] document.
    
               Added in version 215._TTL=_
               A fixed Time To Live N on tunneled packets. N is a number in
               the range 1...255. 0 is a special value meaning that packets
               inherit the TTL value. The default value for IPv4 tunnels is 0
               (inherit). The default value for IPv6 tunnels is 64.
    
               Added in version 215.
    
           _DiscoverPathMTU=_
               Takes a boolean. When true, enables Path MTU Discovery on the
               tunnel. When _IgnoreDontFragment=_ is enabled, defaults to
               false. Otherwise, defaults to true.
    
               Added in version 215.
    
           _IgnoreDontFragment=_
               Takes a boolean. When true, enables IPv4 Don't Fragment (DF)
               suppression on the tunnel. Defaults to false. Note that if
               _IgnoreDontFragment=_ is set to true, _DiscoverPathMTU=_ cannot be
               set to true. Only applicable to GRE, GRETAP, and ERSPAN
               tunnels.
    
               Added in version 254.
    
           _IPv6FlowLabel=_
               Configures the 20-bit flow label (see **RFC 6437******[11]) field in
               the IPv6 header (see**RFC 2460******[12]), which is used by a node to
               label packets of a flow. It is only used for IPv6 tunnels. A
               flow label of zero is used to indicate packets that have not
               been labeled. It can be configured to a value in the range
               0...0xFFFFF, or be set to "inherit", in which case the
               original flowlabel is used.
    
               Added in version 223._CopyDSCP=_
               Takes a boolean. When true, the Differentiated Service Code
               Point (DSCP) field will be copied to the inner header from
               outer header during the decapsulation of an IPv6 tunnel
               packet. DSCP is a field in an IP packet that enables different
               levels of service to be assigned to network traffic. Defaults
               to "no".
    
               Added in version 223.
    
           _EncapsulationLimit=_
               The Tunnel Encapsulation Limit option specifies how many
               additional levels of encapsulation are permitted to be
               prepended to the packet. For example, a Tunnel Encapsulation
               Limit option containing a limit value of zero means that a
               packet carrying that option may not enter another tunnel
               before exiting the current tunnel. (see **RFC 2473******[13]). The
               valid range is 0...255 and "none". Defaults to 4.
    
               Added in version 226._Key=_
               The _Key=_ parameter specifies the same key to use in both
               directions (_InputKey=_ and _OutputKey=_). The _Key=_ is either a
               number or an IPv4 address-like dotted quad. It is used as
               mark-configured SAD/SPD entry as part of the lookup key (both
               in data and control path) in IP XFRM (framework used to
               implement IPsec protocol). See **ip-xfrm — transform**
               **configuration******[14] for details. It is only used for VTI/VTI6,
               GRE, GRETAP, and ERSPAN tunnels.
    
               Added in version 231._InputKey=_
               The _InputKey=_ parameter specifies the key to use for input.
               The format is same as _Key=_. It is only used for VTI/VTI6, GRE,
               GRETAP, and ERSPAN tunnels.
    
               Added in version 231.
    
           _OutputKey=_
               The _OutputKey=_ parameter specifies the key to use for output.
               The format is same as _Key=_. It is only used for VTI/VTI6, GRE,
               GRETAP, and ERSPAN tunnels.
    
               Added in version 231.
    
           _Mode=_
               Specifies the tunnel mode. Acceptable values depend on the
               tunnel kind.
    
               **Table 2. Supported tunnel modes**
               ┌──────────┬──────────┬────────────────────┐
               │ **Kind** │ **Mode** │ **Description** │
               ├──────────┼──────────┼────────────────────┤
               │          │ "ipip"   │ IPv4 over IPv4     │
               │          │          │ (default)          │
               │ "ipip"   ├──────────┼────────────────────┤
               │          │ "any"    │ both IPv4 and IPv6 │
               │          │          │ over IPv4          │
               ├──────────┼──────────┼────────────────────┤
               │          │ "ipip"   │ IPv4 over IPv4     │
               │          ├──────────┼────────────────────┤
               │          │ "ip6ip"  │ IPv6 over IPv4     │
               │ "sit"    │          │ (default)          │
               │          ├──────────┼────────────────────┤
               │          │ "any"    │ both IPv4 and IPv6 │
               │          │          │ over IPv4          │
               ├──────────┼──────────┼────────────────────┤
               │          │ "ipip6"  │ IPv4 over IPv6     │
               │          ├──────────┼────────────────────┤
               │          │ "ip6ip6" │ IPv6 over IPv6     │
               │ "ip6tnl" ├──────────┼────────────────────┤
               │          │ "any"    │ both IPv4 and IPv6 │
               │          │          │ over IPv6          │
               │          │          │ (default)          │
               └──────────┴──────────┴────────────────────┘
    
               Added in version 219.
    
           _Independent=_
               Takes a boolean. When false (the default), the tunnel is
               always created over some network device, and a .network file
               that requests this tunnel using _Tunnel=_ is required for the
               tunnel to be created. When true, the tunnel is created
               independently of any network as "tunnel@NONE".
    
               Added in version 235.
    
           _AssignToLoopback=_
               Takes a boolean. If set to "yes", the loopback interface "lo"
               is used as the underlying device of the tunnel interface.
               Defaults to "no".
    
               Added in version 243.
    
           _AllowLocalRemote=_
               Takes a boolean. When true allows tunnel traffic on _ip6tnl_
               devices where the remote endpoint is a local host address.
               When unset, the kernel's default will be used.
    
               Added in version 237.
    
           _FooOverUDP=_
               Takes a boolean. Specifies whether _FooOverUDP=_ tunnel is to be
               configured. Defaults to false. This takes effects only for
               IPIP, SIT, GRE, and GRETAP tunnels. For more detail
               information see **Foo over UDP******[15]
    
               Added in version 240._FOUDestinationPort=_
               This setting specifies the UDP destination port for
               encapsulation. This field is mandatory when _FooOverUDP=yes_ ,
               and is not set by default.
    
               Added in version 240.
    
           _FOUSourcePort=_
               This setting specifies the UDP source port for encapsulation.
               Defaults to **0** — that is, the source port for packets is left
               to the network stack to decide.
    
               Added in version 240.
    
           _Encapsulation=_
               Accepts the same key as in the [FooOverUDP] section.
    
               Added in version 240.
    
           _IPv6RapidDeploymentPrefix=_
               Reconfigure the tunnel for **IPv6 Rapid Deployment******[16], also
               known as 6rd. The value is an ISP-specific IPv6 prefix with a
               non-zero length. Only applicable to SIT tunnels.
    
               Added in version 240._ISATAP=_
               Takes a boolean. If set, configures the tunnel as Intra-Site
               Automatic Tunnel Addressing Protocol (ISATAP) tunnel. Only
               applicable to SIT tunnels. When unset, the kernel's default
               will be used.
    
               Added in version 240.
    
           _SerializeTunneledPackets=_
               Takes a boolean. If set to yes, then packets are serialized.
               Only applies for GRE, GRETAP, and ERSPAN tunnels. When unset,
               the kernel's default will be used.
    
               Added in version 240.
    
           _ERSPANVersion=_
               Specifies the ERSPAN version number. Takes 0 for version 0
               (a.k.a. type I), 1 for version 1 (a.k.a. type II), or 2 for
               version 2 (a.k.a. type III). Defaults to 1.
    
               Added in version 252.
    
           _ERSPANIndex=_
               Specifies the ERSPAN v1 index field for the interface. Takes
               an integer in the range 0...1048575, which is associated with
               the ERSPAN traffic's source port and direction. Only used when
               _ERSPANVersion=1_. Defaults to 0.
    
               Added in version 240.
    
           _ERSPANDirection=_
               Specifies the ERSPAN v2 mirrored traffic's direction. Takes
               "ingress" or "egress". Only used when _ERSPANVersion=2_.
               Defaults to "ingress".
    
               Added in version 252.
    
           _ERSPANHardwareId=_
               Specifies a unique identifier of the ERSPAN v2 engine. Takes
               an integer in the range 0...63. Only used when
               _ERSPANVersion=2_. Defaults to 0.
    
               Added in version 252.
    


## [FOOOVERUDP] SECTION OPTIONS



           The [FooOverUDP] section only applies for netdevs of kind "fou"
           and accepts the following keys:
    
           _Encapsulation=_
               Specifies the encapsulation mechanism used to store networking
               packets of various protocols inside the UDP packets. Supports
               the following values: "FooOverUDP" provides the simplest
               no-frills model of UDP encapsulation, it simply encapsulates
               packets directly in the UDP payload.
               "GenericUDPEncapsulation" is a generic and extensible
               encapsulation, it allows encapsulation of packets for any IP
               protocol and optional data as part of the encapsulation. For
               more detailed information see **Generic UDP Encapsulation******[17].
               Defaults to "FooOverUDP".
    
               Added in version 240._Port=_
               Specifies the port number where the encapsulated packets will
               arrive. Those packets will be removed and manually fed back
               into the network stack with the encapsulation removed to be
               sent to the real destination. This option is mandatory.
    
               Added in version 240.
    
           _PeerPort=_
               Specifies the peer port number. Defaults to unset. Note that
               when peer port is set "Peer=" address is mandatory.
    
               Added in version 243.
    
           _Protocol=_
               The _Protocol=_ specifies the protocol number of the packets
               arriving at the UDP port. When _Encapsulation=FooOverUDP_ , this
               field is mandatory and is not set by default. Takes an IP
               protocol name such as "gre" or "ipip", or an integer within
               the range 1...255. When _Encapsulation=GenericUDPEncapsulation_ ,
               this must not be specified.
    
               Added in version 240.
    
           _Peer=_
               Configures peer IP address. Note that when peer address is set
               "PeerPort=" is mandatory.
    
               Added in version 243.
    
           _Local=_
               Configures local IP address.
    
               Added in version 243.
    


## [PEER] SECTION OPTIONS



           The [Peer] section only applies for netdevs of kind "veth" and
           accepts the following keys:
    
           _Name=_
               The interface name used when creating the netdev. This setting
               is compulsory.
    
               Added in version 215.
    
           _MACAddress=_
               The peer MACAddress, if not set, it is generated in the same
               way as the MAC address of the main interface.
    
               Added in version 215.
    


## [VXCAN] SECTION OPTIONS



           The [VXCAN] section only applies for netdevs of kind "vxcan" and
           accepts the following key:
    
           _Peer=_
               The peer interface name used when creating the netdev. This
               setting is compulsory.
    
               Added in version 236.
    


## [TUN] SECTION OPTIONS



           The [Tun] section only applies for netdevs of kind "tun", and
           accepts the following keys:
    
           _MultiQueue=_
               Takes a boolean. Configures whether to use multiple file
               descriptors (queues) to parallelize packets sending and
               receiving. Defaults to "no".
    
               Added in version 215.
    
           _PacketInfo=_
               Takes a boolean. Configures whether packets should be
               prepended with four extra bytes (two flag bytes and two
               protocol bytes). If disabled, it indicates that the packets
               will be pure IP packets. Defaults to "no".
    
               Added in version 215.
    
           _VNetHeader=_
               Takes a boolean. Configures IFF_VNET_HDR flag for a tun or tap
               device. It allows sending and receiving larger Generic
               Segmentation Offload (GSO) packets. This may increase
               throughput significantly. Defaults to "no".
    
               Added in version 223.
    
           _User=_
               User to grant access to the /dev/net/tun device. The specified
               user must be a system user.
    
               Added in version 215.
    
           _Group=_
               Group to grant access to the /dev/net/tun device. The
               specified group must be a system group.
    
               Added in version 215.
    
           _KeepCarrier=_
               Takes a boolean. If enabled, to make the interface maintain
               its carrier status, the file descriptor of the interface is
               kept open. This may be useful to keep the interface in running
               state, for example while the backing process is temporarily
               shutdown. Defaults to "no".
    
               Added in version 252.
    


## [TAP] SECTION OPTIONS



           The [Tap] section only applies for netdevs of kind "tap", and
           accepts the same keys as the [Tun] section.
    


## [WIREGUARD] SECTION OPTIONS



           The [WireGuard] section accepts the following keys:
    
           _PrivateKey=_
               The Base64 encoded private key for the interface. It can be
               generated using the **wg genkey** command (see wg(8)). Specially,
               if the specified key is prefixed with "@", it is interpreted
               as the name of the credential from which the actual key shall
               be read.  systemd-networkd.service(8) automatically imports
               credentials matching "network.wireguard.*". For more details
               on credentials, refer to systemd.exec(5). A private key is
               mandatory to use WireGuard. If not set, the credential
               "network.wireguard.private._netdev_ " is used if exists. I.e. for
               50-foobar.netdev, "network.wireguard.private.50-foobar" is
               tried.
    
               Note that because this information is secret, it is strongly
               recommended to use an (encrypted) credential. Alternatively,
               you may want to set the permissions of the .netdev file to be
               owned by "root:systemd-network" with a "0640" file mode.
    
               Added in version 237.
    
           _PrivateKeyFile=_
               Takes an absolute path to a file which contains the Base64
               encoded private key for the interface. When this option is
               specified, then _PrivateKey=_ is ignored. Note that the file
               must be readable by the user "systemd-network", so it should
               be, e.g., owned by "root:systemd-network" with a "0640" file
               mode. If the path refers to an **AF_UNIX** stream socket in the
               file system a connection is made to it and the key read from
               it.
    
               Added in version 242.
    
           _ListenPort=_
               Sets UDP port for listening. Takes either value between 1 and
               65535 or "auto". If "auto" is specified, the port is
               automatically generated based on interface name. Defaults to
               "auto".
    
               Added in version 237.
    
           _FirewallMark=_
               Sets a firewall mark on outgoing WireGuard packets from this
               interface. Takes a number between 1 and 4294967295.
    
               Added in version 243.
    
           _RouteTable=_
               The table identifier for the routes to the addresses specified
               in the _AllowedIPs=_. Takes a negative boolean value, one of the
               predefined names "default", "main", and "local", names defined
               in _RouteTable=_ in networkd.conf(5), or a number in the range
               1...4294967295. When "off" the routes to the addresses
               specified in the _AllowedIPs=_ setting will not be configured.
               Defaults to false. This setting will be ignored when the same
               setting is specified in the [WireGuardPeer] section.
    
               Added in version 250.
    
           _RouteMetric=_
               The priority of the routes to the addresses specified in the
               _AllowedIPs=_. Takes an integer in the range 0...4294967295.
               Defaults to 0 for IPv4 addresses, and 1024 for IPv6 addresses.
               This setting will be ignored when the same setting is
               specified in the [WireGuardPeer] section.
    
               Added in version 250.
    


## [WIREGUARDPEER] SECTION OPTIONS



           The [WireGuardPeer] section accepts the following keys:
    
           _PublicKey=_
               Sets a Base64 encoded public key calculated by **wg pubkey**(see
               wg(8)) from a private key, and usually transmitted out of band
               to the author of the configuration file. This option honors
               the "@" prefix in the same way as the **PrivateKey=** setting of
               the **[WireGuard]** section. This option is mandatory for this
               section.
    
               Added in version 237.
    
           _PublicKeyFile=_
               Takes an absolute path to a file which contains the Base64
               encoded public key for the peer. When this option is
               specified, then _PublicKey=_ will be ignored. Note that the file
               must be readable by the user "systemd-network", so it should
               be, e.g., owned by "root:systemd-network" with a "0640" file
               mode. If the path refers to an **AF_UNIX** stream socket in the
               file system a connection is made to it and the key read from
               it.
    
               Added in version 257.
    
           _PresharedKey=_
               Optional preshared key for the interface. It can be generated
               by the **wg genpsk** command. This option adds an additional layer
               of symmetric-key cryptography to be mixed into the already
               existing public-key cryptography, for post-quantum resistance.
               This option honors the "@" prefix in the same way as the
               **PrivateKey=** setting of the **[WireGuard]** section.
    
               Note that because this information is secret, it is strongly
               recommended to use an (encrypted) credential. Alternatively,
               you may want to set the permissions of the .netdev file to be
               owned by "root:systemd-network" with a "0640" file mode.
    
               Added in version 237.
    
           _PresharedKeyFile=_
               Takes an absolute path to a file which contains the Base64
               encoded preshared key for the peer. When this option is
               specified, then _PresharedKey=_ is ignored. Note that the file
               must be readable by the user "systemd-network", so it should
               be, e.g., owned by "root:systemd-network" with a "0640" file
               mode. If the path refers to an **AF_UNIX** stream socket in the
               file system a connection is made to it and the key read from
               it.
    
               Added in version 242.
    
           _AllowedIPs=_
               Sets a comma-separated list of IP (v4 or v6) addresses with
               CIDR masks from which this peer is allowed to send incoming
               traffic and to which outgoing traffic for this peer is
               directed. This setting can be specified multiple times. If an
               empty string is assigned, then the all previous assignments
               are cleared.
    
               The catch-all 0.0.0.0/0 may be specified for matching all IPv4
               addresses, and ::/0 may be specified for matching all IPv6
               addresses.
    
               Note that this only affects _routing inside the network_
               _interface itself_ , i.e. the packets that pass through the
               tunnel itself. To cause packets to be sent via the tunnel in
               the first place, an appropriate route needs to be added as
               well — either in the "[Routes]" section on the ".network"
               matching the wireguard interface, or externally to
               **systemd-networkd**.
    
               Added in version 237.
    
           _Endpoint=_
               Sets an endpoint IP address or hostname, followed by a colon,
               and then a port number. IPv6 address must be in the square
               brackets. For example, "111.222.333.444:51820" for IPv4 and
               "[1111:2222::3333]:51820" for IPv6 address. This endpoint will
               be updated automatically once to the most recent source IP
               address and port of correctly authenticated packets from the
               peer at configuration time.
    
               This option honors the "@" prefix in the same way as the
               **PrivateKey=** setting of the **[WireGuard]** section.
    
               Added in version 237.
    
           _PersistentKeepalive=_
               Sets a seconds interval, between 1 and 65535 inclusive, of how
               often to send an authenticated empty packet to the peer for
               the purpose of keeping a stateful firewall or NAT mapping
               valid persistently. For example, if the interface very rarely
               sends traffic, but it might at anytime receive traffic from a
               peer, and it is behind NAT, the interface might benefit from
               having a persistent keepalive interval of 25 seconds. If set
               to 0 or "off", this option is disabled. By default or when
               unspecified, this option is off. Most users will not need
               this.
    
               Added in version 237.
    
           _RouteTable=_
               The table identifier for the routes to the addresses specified
               in the _AllowedIPs=_. Takes a negative boolean value, one of the
               predefined names "default", "main", and "local", names defined
               in _RouteTable=_ in networkd.conf(5), or a number in the range
               1...4294967295. Defaults to unset, and the value specified in
               the same setting in the [WireGuard] section will be used.
    
               Added in version 250.
    
           _RouteMetric=_
               The priority of the routes to the addresses specified in the
               _AllowedIPs=_. Takes an integer in the range 0...4294967295.
               Defaults to unset, and the value specified in the same setting
               in the [WireGuard] section will be used.
    
               Added in version 250.
    


## [BOND] SECTION OPTIONS



           The [Bond] section accepts the following key:
    
           _Mode=_
               Specifies one of the bonding policies. The default is
               "balance-rr" (round robin). Possible values are "balance-rr",
               "active-backup", "balance-xor", "broadcast", "802.3ad",
               "balance-tlb", and "balance-alb".
    
               Added in version 216.
    
           _TransmitHashPolicy=_
               Selects the transmit hash policy to use for slave selection in
               balance-xor, 802.3ad, and tlb modes. Possible values are
               "layer2", "layer3+4", "layer2+3", "encap2+3", and "encap3+4".
    
               Added in version 216.
    
           _LACPTransmitRate=_
               Specifies the rate with which link partner transmits Link
               Aggregation Control Protocol Data Unit packets in 802.3ad
               mode. Possible values are "slow", which requests partner to
               transmit LACPDUs every 30 seconds, and "fast", which requests
               partner to transmit LACPDUs every second. The default value is
               "slow".
    
               Added in version 216.
    
           _MIIMonitorSec=_
               Specifies the frequency that Media Independent Interface link
               monitoring will occur. A value of zero disables MII link
               monitoring. This value is rounded down to the nearest
               millisecond. The default value is 0.
    
               Added in version 216.
    
           _PeerNotifyDelaySec=_
               Specifies the number of seconds the delay between each peer
               notification (gratuitous ARP and unsolicited IPv6 Neighbor
               Advertisement) when they are issued after a failover event.
               This delay should be a multiple of the MII link monitor
               interval (miimon). The valid range is 0...300s. The default
               value is 0, which means to match the value of the
               _MIIMonitorSec=_.
    
               Added in version 256.
    
           _UpDelaySec=_
               Specifies the delay before a link is enabled after a link up
               status has been detected. This value is rounded down to a
               multiple of _MIIMonitorSec=_. The default value is 0.
    
               Added in version 216.
    
           _DownDelaySec=_
               Specifies the delay before a link is disabled after a link
               down status has been detected. This value is rounded down to a
               multiple of _MIIMonitorSec=_. The default value is 0.
    
               Added in version 216.
    
           _LearnPacketIntervalSec=_
               Specifies the number of seconds between instances where the
               bonding driver sends learning packets to each slave peer
               switch. The valid range is 1...0x7fffffff; the default value
               is 1. This option has an effect only for the balance-tlb and
               balance-alb modes.
    
               Added in version 220.
    
           _AdSelect=_
               Specifies the 802.3ad aggregation selection logic to use.
               Possible values are "stable", "bandwidth" and "count".
    
               Added in version 220.
    
           _AdActorSystemPriority=_
               Specifies the 802.3ad actor system priority. Takes a number in
               the range 1...65535.
    
               Added in version 240.
    
           _AdUserPortKey=_
               Specifies the 802.3ad user defined portion of the port key.
               Takes a number in the range 0...1023.
    
               Added in version 240.
    
           _AdActorSystem=_
               Specifies the 802.3ad system MAC address. This cannot be a
               null or multicast address.
    
               Added in version 240.
    
           _FailOverMACPolicy=_
               Specifies whether the active-backup mode should set all slaves
               to the same MAC address at the time of enslavement or, when
               enabled, to perform special handling of the bond's MAC address
               in accordance with the selected policy. The default policy is
               none. Possible values are "none", "active" and "follow".
    
               Added in version 220.
    
           _ARPValidate=_
               Specifies whether or not ARP probes and replies should be
               validated in any mode that supports ARP monitoring, or whether
               non-ARP traffic should be filtered (disregarded) for link
               monitoring purposes. Possible values are "none", "active",
               "backup" and "all".
    
               Added in version 220.
    
           _ARPIntervalSec=_
               Specifies the ARP link monitoring frequency. A value of 0
               disables ARP monitoring. The default value is 0, and the
               default unit seconds.
    
               Added in version 220.
    
           _ARPIPTargets=_
               Specifies the IP addresses to use as ARP monitoring peers when
               _ARPIntervalSec=_ is greater than 0. These are the targets of
               the ARP request sent to determine the health of the link to
               the targets. Specify these values in IPv4 dotted decimal
               format. At least one IP address must be given for ARP
               monitoring to function. The maximum number of targets that can
               be specified is 16. The default value is no IP addresses.
    
               Added in version 220.
    
           _ARPAllTargets=_
               Specifies the quantity of _ARPIPTargets=_ that must be reachable
               in order for the ARP monitor to consider a slave as being up.
               This option affects only active-backup mode for slaves with
               ARPValidate enabled. Possible values are "any" and "all".
    
               Added in version 220.
    
           _PrimaryReselectPolicy=_
               Specifies the reselection policy for the primary slave. This
               affects how the primary slave is chosen to become the active
               slave when failure of the active slave or recovery of the
               primary slave occurs. This option is designed to prevent
               flip-flopping between the primary slave and other slaves.
               Possible values are "always", "better" and "failure".
    
               Added in version 220.
    
           _ResendIGMP=_
               Specifies the number of IGMP membership reports to be issued
               after a failover event. One membership report is issued
               immediately after the failover, subsequent packets are sent in
               each 200ms interval. The valid range is 0...255. Defaults to
               1. A value of 0 prevents the IGMP membership report from being
               issued in response to the failover event.
    
               Added in version 220.
    
           _PacketsPerSlave=_
               Specify the number of packets to transmit through a slave
               before moving to the next one. When set to 0, then a slave is
               chosen at random. The valid range is 0...65535. Defaults to 1.
               This option only has effect when in balance-rr mode.
    
               Added in version 220.
    
           _GratuitousARP=_
               Specify the number of peer notifications (gratuitous ARPs and
               unsolicited IPv6 Neighbor Advertisements) to be issued after a
               failover event. As soon as the link is up on the new slave, a
               peer notification is sent on the bonding device and each VLAN
               sub-device. This is repeated at each link monitor interval
               (ARPIntervalSec or MIIMonitorSec, whichever is active) if the
               number is greater than 1. The valid range is 0...255. The
               default value is 1. These options affect only the
               active-backup mode.
    
               Added in version 220.
    
           _AllSlavesActive=_
               Takes a boolean. Specifies that duplicate frames (received on
               inactive ports) should be dropped when false, or delivered
               when true. Normally, bonding will drop duplicate frames
               (received on inactive ports), which is desirable for most
               users. But there are some cases where it is nice to allow
               duplicate frames to be delivered. The default value is false
               (drop duplicate frames received on inactive ports).
    
               Added in version 220.
    
           _DynamicTransmitLoadBalancing=_
               Takes a boolean. Specifies if dynamic shuffling of flows is
               enabled. Applies only for balance-tlb mode. Defaults to unset.
    
               Added in version 240.
    
           _MinLinks=_
               Specifies the minimum number of links that must be active
               before asserting carrier. The default value is 0.
    
               Added in version 220.
    
           _ARPMissedMax=_
               Specify the maximum number of arp interval monitor cycle for
               missed ARP replies. If this number is exceeded, link is
               reported as down. Defaults to unset.
    
               Added in version 256.
    
           For more detail information see **Linux Ethernet Bonding Driver**
           **HOWTO******[1]


## [XFRM] SECTION OPTIONS



           The [Xfrm] section accepts the following keys:
    
           _InterfaceId=_
               Sets the ID/key of the xfrm interface which needs to be
               associated with a SA/policy. Can be decimal or hexadecimal,
               valid range is 1-0xffffffff. This is mandatory.
    
               Added in version 243.
    
           _Independent=_
               Takes a boolean. If false (the default), the xfrm interface
               must have an underlying device which can be used for hardware
               offloading.
    
               Added in version 243.
    
           For more detail information see **Virtual XFRM Interfaces******[18].


## [VRF] SECTION OPTIONS



           The [VRF] section only applies for netdevs of kind "vrf" and
           accepts the following key:
    
           _Table=_
               The numeric routing table identifier. This setting is
               compulsory.
    
               Added in version 243.
    


## [BATMANADVANCED] SECTION OPTIONS



           The [BatmanAdvanced] section only applies for netdevs of kind
           "batadv" and accepts the following keys:
    
           _GatewayMode=_
               Takes one of "off", "server", or "client". A batman-adv node
               can either run in server mode (sharing its internet connection
               with the mesh) or in client mode (searching for the most
               suitable internet connection in the mesh) or having the
               gateway support turned off entirely (which is the default
               setting).
    
               Added in version 248.
    
           _Aggregation=_
               Takes a boolean value. Enables or disables aggregation of
               originator messages. Defaults to true.
    
               Added in version 248.
    
           _BridgeLoopAvoidance=_
               Takes a boolean value. Enables or disables avoidance of loops
               on bridges. Defaults to true.
    
               Added in version 248.
    
           _DistributedArpTable=_
               Takes a boolean value. Enables or disables the distributed ARP
               table. Defaults to true.
    
               Added in version 248.
    
           _Fragmentation=_
               Takes a boolean value. Enables or disables fragmentation.
               Defaults to true.
    
               Added in version 248.
    
           _HopPenalty=_
               The hop penalty setting allows one to modify **batctl**(8)
               preference for multihop routes vs. short routes. This integer
               value is applied to the TQ (Transmit Quality) of each
               forwarded OGM (Originator Message), thereby propagating the
               cost of an extra hop (the packet has to be received and
               retransmitted which costs airtime). A higher hop penalty will
               make it more unlikely that other nodes will choose this node
               as intermediate hop towards any given destination. The default
               hop penalty of '15' is a reasonable value for most setups and
               probably does not need to be changed. However, mobile nodes
               could choose a value of 255 (maximum value) to avoid being
               chosen as a router by other nodes. The minimum value is 0.
    
               Added in version 248.
    
           _OriginatorIntervalSec=_
               The value specifies the interval in seconds, unless another
               time unit is specified in which batman-adv floods the network
               with its protocol information. See systemd.time(7) for more
               information.
    
               Added in version 248.
    
           _GatewayBandwidthDown=_
               If the node is a server, this parameter is used to inform
               other nodes in the network about this node's internet
               connection download bandwidth in bits per second. Just enter
               any number suffixed with K, M, G or T (base 1000) and the
               batman-adv module will propagate the entered value in the
               mesh.
    
               Added in version 248.
    
           _GatewayBandwidthUp=_
               If the node is a server, this parameter is used to inform
               other nodes in the network about this node's internet
               connection upload bandwidth in bits per second. Just enter any
               number suffixed with K, M, G or T (base 1000) and the
               batman-adv module will propagate the entered value in the
               mesh.
    
               Added in version 248.
    
           _RoutingAlgorithm=_
               This can be either "batman-v" or "batman-iv" and describes
               which routing_algo of **batctl**(8) to use. The algorithm cannot
               be changed after interface creation. Defaults to "batman-v".
    
               Added in version 248.
    


## [IPOIB] SECTION OPTIONS



           The [IPoIB] section only applies for netdevs of kind "ipoib" and
           accepts the following keys:
    
           _PartitionKey=_
               Takes an integer in the range 1...0xffff, except for 0x8000.
               Defaults to unset, and the kernel's default is used.
    
               Added in version 250.
    
           _Mode=_
               Takes one of the special values "datagram" or "connected".
               Defaults to unset, and the kernel's default is used.
    
               When "datagram", the Infiniband unreliable datagram (UD)
               transport is used, and so the interface MTU is equal to the IB
               L2 MTU minus the IPoIB encapsulation header (4 bytes). For
               example, in a typical IB fabric with a 2K MTU, the IPoIB MTU
               will be 2048 - 4 = 2044 bytes.
    
               When "connected", the Infiniband reliable connected (RC)
               transport is used. Connected mode takes advantage of the
               connected nature of the IB transport and allows an MTU up to
               the maximal IP packet size of 64K, which reduces the number of
               IP packets needed for handling large UDP datagrams, TCP
               segments, etc and increases the performance for large
               messages.
    
               Added in version 250.
    
           _IgnoreUserspaceMulticastGroups=_
               Takes a boolean value. When true, the kernel ignores multicast
               groups handled by userspace. Defaults to unset, and the
               kernel's default is used.
    
               Added in version 250.
    


## [WLAN] SECTION OPTIONS



           The [WLAN] section only applies to WLAN interfaces, and accepts
           the following keys:
    
           _PhysicalDevice=_
               Specifies the name or index of the physical WLAN device (e.g.
               "0" or "phy0"). The list of the physical WLAN devices that
               exist on the host can be obtained by **iw phy** command. This
               option is mandatory.
    
               Added in version 251.
    
           _Type=_
               Specifies the type of the interface. Takes one of the
               "ad-hoc", "station", "ap", "ap-vlan", "wds", "monitor",
               "mesh-point", "p2p-client", "p2p-go", "p2p-device", "ocb", and
               "nan". This option is mandatory.
    
               Added in version 251.
    
           _WDS=_
               Enables the Wireless Distribution System (WDS) mode on the
               interface. The mode is also known as the "4 address mode".
               Takes a boolean value. Defaults to unset, and the kernel's
               default will be used.
    
               Added in version 251.
    


## EXAMPLES



           **Example 1. /etc/systemd/network/25-bridge.netdev**
    
               [NetDev]
               Name=bridge0
               Kind=bridge
    
           **Example 2. /etc/systemd/network/25-vlan1.netdev**
    
               [Match]
               Virtualization=no
    
               [NetDev]
               Name=vlan1
               Kind=vlan
    
               [VLAN]
               Id=1
    
           **Example 3. /etc/systemd/network/25-ipip.netdev**
    
               [NetDev]
               Name=ipip-tun
               Kind=ipip
               MTUBytes=1480
    
               [Tunnel]
               Local=192.168.223.238
               Remote=192.169.224.239
               TTL=64
    
           **Example 4. /etc/systemd/network/1-fou-tunnel.netdev**
    
               [NetDev]
               Name=fou-tun
               Kind=fou
    
               [FooOverUDP]
               Port=5555
               Protocol=4
    
           **Example 5. /etc/systemd/network/25-fou-ipip.netdev**
    
               [NetDev]
               Name=ipip-tun
               Kind=ipip
    
               [Tunnel]
               Independent=yes
               Local=10.65.208.212
               Remote=10.65.208.211
               FooOverUDP=yes
               FOUDestinationPort=5555
    
           **Example 6. /etc/systemd/network/25-tap.netdev**
    
               [NetDev]
               Name=tap-test
               Kind=tap
    
               [Tap]
               MultiQueue=yes
               PacketInfo=yes
    
           **Example 7. /etc/systemd/network/25-sit.netdev**
    
               [NetDev]
               Name=sit-tun
               Kind=sit
               MTUBytes=1480
    
               [Tunnel]
               Local=10.65.223.238
               Remote=10.65.223.239
    
           **Example 8. /etc/systemd/network/25-6rd.netdev**
    
               [NetDev]
               Name=6rd-tun
               Kind=sit
               MTUBytes=1480
    
               [Tunnel]
               Local=10.65.223.238
               IPv6RapidDeploymentPrefix=2602::/24
    
           **Example 9. /etc/systemd/network/25-gre.netdev**
    
               [NetDev]
               Name=gre-tun
               Kind=gre
               MTUBytes=1480
    
               [Tunnel]
               Local=10.65.223.238
               Remote=10.65.223.239
    
           **Example 10. /etc/systemd/network/25-ip6gre.netdev**
    
               [NetDev]
               Name=ip6gre-tun
               Kind=ip6gre
    
               [Tunnel]
               Key=123
    
           **Example 11. /etc/systemd/network/25-vti.netdev**
    
               [NetDev]
               Name=vti-tun
               Kind=vti
               MTUBytes=1480
    
               [Tunnel]
               Local=10.65.223.238
               Remote=10.65.223.239
    
           **Example 12. /etc/systemd/network/25-veth.netdev**
    
               [NetDev]
               Name=veth-test
               Kind=veth
    
               [Peer]
               Name=veth-peer
    
           **Example 13. /etc/systemd/network/25-bond.netdev**
    
               [NetDev]
               Name=bond1
               Kind=bond
    
               [Bond]
               Mode=802.3ad
               TransmitHashPolicy=layer3+4
               MIIMonitorSec=1s
               LACPTransmitRate=fast
    
           **Example 14. /etc/systemd/network/25-dummy.netdev**
    
               [NetDev]
               Name=dummy-test
               Kind=dummy
               MACAddress=12:34:56:78:9a:bc
    
           **Example 15. /etc/systemd/network/25-vrf.netdev**
    
           Create a VRF interface with table 42.
    
               [NetDev]
               Name=vrf-test
               Kind=vrf
    
               [VRF]
               Table=42
    
           **Example 16. /etc/systemd/network/25-macvtap.netdev**
    
           Create a MacVTap device.
    
               [NetDev]
               Name=macvtap-test
               Kind=macvtap
    
           **Example 17. /etc/systemd/network/25-wireguard.netdev**
    
               [NetDev]
               Name=wg0
               Kind=wireguard
    
               [WireGuard]
               PrivateKey=EEGlnEPYJV//kbvvIqxKkQwOiS+UENyPncC4bF46ong=
               ListenPort=51820
    
               [WireGuardPeer]
               PublicKey=RDf+LSpeEre7YEIKaxg+wbpsNV7du+ktR99uBEtIiCA=
               AllowedIPs=fd31:bf08:57cb::/48,192.168.26.0/24
               Endpoint=wireguard.example.com:51820
    
           **Example 18. /etc/systemd/network/27-xfrm.netdev**
    
               [NetDev]
               Name=xfrm0
               Kind=xfrm
    
               [Xfrm]
               Independent=yes
    


## NOTES



            1. Linux Ethernet Bonding Driver HOWTO
               https://docs.kernel.org/networking/bonding.html
    
            2. RFC 2784
               https://tools.ietf.org/html/rfc2784
    
            3. IEEE 802.1Q
               http://www.ieee802.org/1/pages/802.1Q.html
    
            4. VRF
               https://docs.kernel.org/networking/vrf.html
    
            5. B.A.T.M.A.N. Advanced
               https://www.open-mesh.org/projects/open-mesh/wiki
    
            6. System and Service Credentials
               https://systemd.io/CREDENTIALS
    
            7. Distributed Overlay Virtual Ethernet (DOVE)
               https://en.wikipedia.org/wiki/Distributed_Overlay_Virtual_Ethernet
    
            8. VXLAN Group Policy
               https://tools.ietf.org/html/draft-smith-vxlan-group-policy
    
            9. Generic Protocol Extension for VXLAN
               https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe-07
    
           10. Type of Service in the Internet Protocol Suite
               http://tools.ietf.org/html/rfc1349
    
           11. RFC 6437
               https://tools.ietf.org/html/rfc6437
    
           12. RFC 2460
               https://tools.ietf.org/html/rfc2460
    
           13. RFC 2473
               https://tools.ietf.org/html/rfc2473#section-4.1.1
    
           14. ip-xfrm — transform configuration
               https://man7.org/linux/man-pages/man8/ip-xfrm.8.html
    
           15. Foo over UDP
               https://lwn.net/Articles/614348
    
           16. IPv6 Rapid Deployment
               https://tools.ietf.org/html/rfc5569
    
           17. Generic UDP Encapsulation
               https://lwn.net/Articles/615044
    
           18. Virtual XFRM Interfaces
               https://lwn.net/Articles/757391
    


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