systemd Developer Tom Gundersen teg@jklm.no systemd.netdev 5 systemd.netdev Virtual Network Device configuration netdev.netdev Network setup is performed by systemd-networkd8. Virtual Network Device files must have the extension .netdev; other extensions are ignored. Virtual network devices are created as soon as networkd is started. If a netdev with the specified name already exists, networkd will use that as-is rather than create its own. Note that the settings of the pre-existing netdev will not be changed by networkd. The .netdev files are read from the files located in the system network directory /usr/lib/systemd/network, the volatile runtime network directory /run/systemd/network and the local administration network directory /etc/systemd/network. All configuration files are collectively sorted and processed in lexical order, regardless of the directories in which they live. However, files with identical filenames replace each other. Files in /etc have the highest priority, files in /run take precedence over files with the same name in /usr/lib. This can be used to override a system-supplied configuration file with a local file if needed; a symlink in /etc with the same name as a configuration file in /usr/lib, pointing to /dev/null, disables the configuration file entirely. The following kinds of virtual network devices may be configured in .netdev files: bond A bond device is an aggregation of all its slave devices. See Linux Ethernet Bonding Driver HOWTO for details. bridge A bridge devcie is a software switch, 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 for details. gretap A Level 2 GRE tunnel over IPv4. ip6gre A Level 3 GRE tunnel over IPv6. ip6tnl An IPv4 or IPv6 tunnel over IPv6 ip6gretap An 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. macvlan A macvlan 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 for details. vti An IPv4 over IPSec tunnel. vxlan 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.unit5 for details. Virtualization= Checks whether the system is executed in a virtualized environment and optionally test whether it is a specific implementation. See ConditionVirtualization= in systemd.unit5 for details. KernelCommandLine= Checks whether a specific kernel command line option is set (or if prefixed with the exclamation mark unset). See ConditionKernelCommandLine= in systemd.unit5 for details. Architecture= Checks whether the system is running on a specific architecture. See ConditionArchitecture= in systemd.unit5 for details. The [NetDev] section accepts the following keys: Description= A free-form description of the netdev. Name= The interface name used when creating the netdev. This option is compulsory. Kind= The netdev kind. This option is compulsory. See the Supported netdev kinds section for the valid keys. 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. This key is not currently suported for tun or tap devices. MACAddress= The MAC address to use for the device. If none is given, one is generated based on the interface name and the machine-id5. This key is not currently suported for tun or tap devices. 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 option is compulsory. 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 and passthru. 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 and L3. The [VXLAN] section only applies for netdevs of kind vxlan, and accepts the following key: Id= The VXLAN ID to use. Group= An assigned multicast group IP address. TOS= The Type Of Service byte value for a vxlan interface. TTL= A fixed Time To Live N on Virtual eXtensible Local Area Network packets. N is a number in the range 1-255. 0 is a special value meaning that packets inherit the TTL value. MacLearning= A boolean. When true, enables dynamic MAC learning to discover remote MAC addresses. FDBAgeingSec= The lifetime of Forwarding Database entry learnt by the kernel in seconds. ARPProxy= A boolean. When true, enables ARP proxy. L2MissNotification= A boolean. When true, enables netlink LLADDR miss notifications. L3MissNotification= A boolean. When true, enables netlink IP ADDR miss notifications. RouteShortCircuit= A boolean. When true route short circuit is turned on. The [Tunnel] section only applies for netdevs of kind ipip, sit, gre, gretap, ip6gre, ip6gretap, vti and ip6tnl and accepts the following keys: Local= A static local address for tunneled packets. It must be an address on another interface of this host. Remote= The remote endpoint of the tunnel. 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 document. 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: inherit. The default value for IPv6 tunnels is: 64. DiscoverPathMTU= A boolean. When true, enables Path MTU Discovery on the tunnel. Mode= An ip6tnl tunnels can have three modes ip6ip6 for IPv6 over IPv6, ipip6 for IPv4 over IPv6 or any for either. The [Peer] section only applies for netdevs of kind veth and accepts the following key: Name= The interface name used when creating the netdev. This option is compulsory. MACAddress= The peer MACAddress, if not set it is generated in the same way as the MAC address of the main interface. The [Tun] section only applies for netdevs of kind tun, and accepts the following keys: OneQueue= Takes a boolean argument. Configures whether all packets are queued at the device (enabled), or a fixed number of packets are queued at the device and the rest at the qdisc. Defaults to no. MultiQueue= Takes a boolean argument. Configures whether to use multiple file descriptors (queues) to parallelize packets sending and receiving. Defaults to no. PacketInfo= Takes a boolean argument. Configures whether packets should be prepened 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. User= User to grant access to the /dev/net/tun device. Group= Group to grant access to the /dev/net/tun device. The [Tap] section only applies for netdevs of kind tap, and accepts the same keys as the [Tun] section. 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. 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, 802.3ad, and encap3+4. 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. MIIMonitorSec= Specifies the frequency that Media Independent Interface link monitoring will occur. A value of zero disables MII link monitoring. This values is rounded down to the nearest millisecond. The default value is 0. 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. 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. [NetDev] Name=bridge0 Kind=bridge [Match] Virtualization=no [NetDev] Name=vlan1 Kind=vlan [VLAN] Id=1 [NetDev] Name=ipip-tun Kind=ipip MTUBytes=1480 [Tunnel] Local=192.168.223.238 Remote=192.169.224.239 TTL=64 [NetDev] Name=tap-test Kind=tap [Tap] MultiQueue=true PacketInfo=true [NetDev] Name=sit-tun Kind=sit MTUBytes=1480 [Tunnel] Local=10.65.223.238 Remote=10.65.223.239 [NetDev] Name=gre-tun Kind=gre MTUBytes=1480 [Tunnel] Local=10.65.223.238 Remote=10.65.223.239 [NetDev] Name=vti-tun Kind=vti MTUBytes=1480 [Tunnel] Local=10.65.223.238 Remote=10.65.223.239 [NetDev] Name=veth-test Kind=veth [Peer] Name=veth-peer [NetDev] Name=dummy-test Kind=dummy MACAddress=12:34:56:78:9a:bc systemd1, systemd-networkd8, systemd.link5, systemd.network5