1SYSTEMD.NETWORK(5) systemd.network SYSTEMD.NETWORK(5)
2
6 systemd.network - Network configuration
7
9 network.network
10
12 A plain ini-style text file that encodes network configuration for
13 matching network interfaces, used by systemd-networkd(8). See
14 systemd.syntax(7) for a general description of the syntax.
15 The main network file must have the extension .network; other
17 extensions are ignored. Networks are applied to links whenever the
18 links appear.
19 The .network files are read from the files located in the system
21 network directories /usr/lib/systemd/network and
22 /usr/local/lib/systemd/network, the volatile runtime network directory
23 /run/systemd/network and the local administration network directory
24 /etc/systemd/network. All configuration files are collectively sorted
25 and processed in lexical order, regardless of the directories in which
26 they live. However, files with identical filenames replace each other.
27 Files in /etc have the highest priority, files in /run take precedence
28 over files with the same name under /usr. This can be used to override
29 a system-supplied configuration file with a local file if needed. As a
30 special case, an empty file (file size 0) or symlink with the same name
31 pointing to /dev/null disables the configuration file entirely (it is
32 "masked").
33 Along with the network file foo.network, a "drop-in" directory
35 foo.network.d/ may exist. All files with the suffix ".conf" from this
36 directory will be parsed after the file itself is parsed. This is
37 useful to alter or add configuration settings, without having to modify
38 the main configuration file. Each drop-in file must have appropriate
39 section headers.
40 In addition to /etc/systemd/network, drop-in ".d" directories can be
42 placed in /usr/lib/systemd/network or /run/systemd/network directories.
43 Drop-in files in /etc take precedence over those in /run which in turn
44 take precedence over those in /usr/lib. Drop-in files under any of
45 these directories take precedence over the main network file wherever
46 located.
47
49 The network file contains a [Match] section, which determines if a
50 given network file may be applied to a given device; and a [Network]
51 section specifying how the device should be configured. The first (in
52 lexical order) of the network files that matches a given device is
53 applied, all later files are ignored, even if they match as well.
54 A network file is said to match a network interface if all matches
56 specified by the [Match] section are satisfied. When a network file
57 does not contain valid settings in [Match] section, then the file will
58 match all interfaces and systemd-networkd warns about that. Hint: to
59 avoid the warning and to make it clear that all interfaces shall be
60 matched, add the following:
61 Name=*
63 The following keys are accepted:
65 MACAddress=
67 A whitespace-separated list of hardware addresses. Use full colon-,
68 hyphen- or dot-delimited hexadecimal. See the example below. This
69 option may appear more than once, in which case the lists are
70 merged. If the empty string is assigned to this option, the list of
71 hardware addresses defined prior to this is reset.
72 Example:
74 MACAddress=01:23:45:67:89:ab 00-11-22-33-44-55 AABB.CCDD.EEFF
76 PermanentMACAddress=
78 A whitespace-separated list of hardware's permanent addresses.
79 While MACAddress= matches the device's current MAC address, this
80 matches the device's permanent MAC address, which may be different
81 from the current one. Use full colon-, hyphen- or dot-delimited
82 hexadecimal. This option may appear more than once, in which case
83 the lists are merged. If the empty string is assigned to this
84 option, the list of hardware addresses defined prior to this is
85 reset.
86 Path=
88 A whitespace-separated list of shell-style globs matching the
89 persistent path, as exposed by the udev property ID_PATH.
90 Driver=
92 A whitespace-separated list of shell-style globs matching the
93 driver currently bound to the device, as exposed by the udev
94 property ID_NET_DRIVER of its parent device, or if that is not set,
95 the driver as exposed by ethtool -i of the device itself. If the
96 list is prefixed with a "!", the test is inverted.
97 Type=
99 A whitespace-separated list of shell-style globs matching the
100 device type, as exposed by networkctl status. If the list is
101 prefixed with a "!", the test is inverted.
102 Property=
104 A whitespace-separated list of udev property name with its value
105 after a equal ("="). If multiple properties are specified, the test
106 results are ANDed. If the list is prefixed with a "!", the test is
107 inverted. If a value contains white spaces, then please quote whole
108 key and value pair. If a value contains quotation, then please
109 escape the quotation with "\".
110 Example: if a .link file has the following:
112 Property=ID_MODEL_ID=9999 "ID_VENDOR_FROM_DATABASE=vendor name" "KEY=with \"quotation\""
114 then, the .link file matches only when an interface has all the
116 above three properties.
117 Name=
119 A whitespace-separated list of shell-style globs matching the
120 device name, as exposed by the udev property "INTERFACE", or
121 device's alternative names. If the list is prefixed with a "!", the
122 test is inverted.
123 WLANInterfaceType=
125 A whitespace-separated list of wireless network type. Supported
126 values are "ad-hoc", "station", "ap", "ap-vlan", "wds", "monitor",
127 "mesh-point", "p2p-client", "p2p-go", "p2p-device", "ocb", and
128 "nan". If the list is prefixed with a "!", the test is inverted.
129 SSID=
131 A whitespace-separated list of shell-style globs matching the SSID
132 of the currently connected wireless LAN. If the list is prefixed
133 with a "!", the test is inverted.
134 BSSID=
136 A whitespace-separated list of hardware address of the currently
137 connected wireless LAN. Use full colon-, hyphen- or dot-delimited
138 hexadecimal. See the example in MACAddress=. This option may appear
139 more than once, in which case the lists are merged. If the empty
140 string is assigned to this option, the list is reset.
141 Host=
143 Matches against the hostname or machine ID of the host. See
144 ConditionHost= in systemd.unit(5) for details. When prefixed with
145 an exclamation mark ("!"), the result is negated. If an empty
146 string is assigned, then previously assigned value is cleared.
147 Virtualization=
149 Checks whether the system is executed in a virtualized environment
150 and optionally test whether it is a specific implementation. See
151 ConditionVirtualization= in systemd.unit(5) for details. When
152 prefixed with an exclamation mark ("!"), the result is negated. If
153 an empty string is assigned, then previously assigned value is
154 cleared.
155 KernelCommandLine=
157 Checks whether a specific kernel command line option is set. See
158 ConditionKernelCommandLine= in systemd.unit(5) for details. When
159 prefixed with an exclamation mark ("!"), the result is negated. If
160 an empty string is assigned, then previously assigned value is
161 cleared.
162 KernelVersion=
164 Checks whether the kernel version (as reported by uname -r) matches
165 a certain expression. See ConditionKernelVersion= in
166 systemd.unit(5) for details. When prefixed with an exclamation mark
167 ("!"), the result is negated. If an empty string is assigned, then
168 previously assigned value is cleared.
169 Architecture=
171 Checks whether the system is running on a specific architecture.
172 See ConditionArchitecture= in systemd.unit(5) for details. When
173 prefixed with an exclamation mark ("!"), the result is negated. If
174 an empty string is assigned, then previously assigned value is
175 cleared.
176
178 The [Link] section accepts the following keys:
179 MACAddress=
181 The hardware address to set for the device.
182 MTUBytes=
184 The maximum transmission unit in bytes to set for the device. The
185 usual suffixes K, M, G, are supported and are understood to the
186 base of 1024.
187 Note that if IPv6 is enabled on the interface, and the MTU is
189 chosen below 1280 (the minimum MTU for IPv6) it will automatically
190 be increased to this value.
191 ARP=
193 Takes a boolean. If set to true, the ARP (low-level Address
194 Resolution Protocol) for this interface is enabled. When unset, the
195 kernel's default will be used.
196 For example, disabling ARP is useful when creating multiple MACVLAN
198 or VLAN virtual interfaces atop a single lower-level physical
199 interface, which will then only serve as a link/"bridge" device
200 aggregating traffic to the same physical link and not participate
201 in the network otherwise.
202 Multicast=
204 Takes a boolean. If set to true, the multicast flag on the device
205 is enabled.
206 AllMulticast=
208 Takes a boolean. If set to true, the driver retrieves all multicast
209 packets from the network. This happens when multicast routing is
210 enabled.
211 Unmanaged=
213 Takes a boolean. When "yes", no attempts are made to bring up or
214 configure matching links, equivalent to when there are no matching
215 network files. Defaults to "no".
216 This is useful for preventing later matching network files from
218 interfering with certain interfaces that are fully controlled by
219 other applications.
220 Group=
222 Link groups are similar to port ranges found in managed switches.
223 When network interfaces are added to a numbered group, operations
224 on all the interfaces from that group can be performed at once. An
225 unsigned integer in the range 0—4294967294. Defaults to unset.
226 RequiredForOnline=
228 Takes a boolean or a minimum operational state and an optional
229 maximum operational state. Please see networkctl(1) for possible
230 operational states. When "yes", the network is deemed required when
231 determining whether the system is online when running
232 systemd-networkd-wait-online. When "no", the network is ignored
233 when checking for online state. When a minimum operational state
234 and an optional maximum operational state are set, "yes" is
235 implied, and this controls the minimum and maximum operational
236 state required for the network interface to be considered online.
237 Defaults to "yes".
238 The network will be brought up normally in all cases, but in the
240 event that there is no address being assigned by DHCP or the cable
241 is not plugged in, the link will simply remain offline and be
242 skipped automatically by systemd-networkd-wait-online if
243 "RequiredForOnline=no".
244
246 The [SR-IOV] section accepts the following keys. Specify several
247 [SR-IOV] sections to configure several SR-IOVs. SR-IOV provides the
248 ability to partition a single physical PCI resource into virtual PCI
249 functions which can then be injected into a VM. In the case of network
250 VFs, SR-IOV improves north-south network performance (that is, traffic
251 with endpoints outside the host machine) by allowing traffic to bypass
252 the host machine’s network stack.
253 VirtualFunction=
255 Specifies a Virtual Function (VF), lightweight PCIe function
256 designed solely to move data in and out. Takes an unsigned integer
257 in the range 0..2147483646. This option is compulsory.
258 VLANId=
260 Specifies VLAN ID of the virtual function. Takes an unsigned
261 integer in the range 1..4095.
262 QualityOfService=
264 Specifies quality of service of the virtual function. Takes an
265 unsigned integer in the range 1..4294967294.
266 VLANProtocol=
268 Specifies VLAN protocol of the virtual function. Takes "802.1Q" or
269 "802.1ad".
270 MACSpoofCheck=
272 Takes a boolean. Controls the MAC spoof checking. When unset, the
273 kernel's default will be used.
274 QueryReceiveSideScaling=
276 Takes a boolean. Toggle the ability of querying the receive side
277 scaling (RSS) configuration of the virtual function (VF). The VF
278 RSS information like RSS hash key may be considered sensitive on
279 some devices where this information is shared between VF and the
280 physical function (PF). When unset, the kernel's default will be
281 used.
282 Trust=
284 Takes a boolean. Allows to set trust mode of the virtual function
285 (VF). When set, VF users can set a specific feature which may
286 impact security and/or performance. When unset, the kernel's
287 default will be used.
288 LinkState=
290 Allows to set the link state of the virtual function (VF). Takes a
291 boolean or a special value "auto". Setting to "auto" means a
292 reflection of the physical function (PF) link state, "yes" lets the
293 VF to communicate with other VFs on this host even if the PF link
294 state is down, "no" causes the hardware to drop any packets sent by
295 the VF. When unset, the kernel's default will be used.
296 MACAddress=
298 Specifies the MAC address for the virtual function.
299
301 The [Network] section accepts the following keys:
302 Description=
304 A description of the device. This is only used for presentation
305 purposes.
306 DHCP=
308 Enables DHCPv4 and/or DHCPv6 client support. Accepts "yes", "no",
309 "ipv4", or "ipv6". Defaults to "no".
310 Note that DHCPv6 will by default be triggered by Router
312 Advertisement, if that is enabled, regardless of this parameter. By
313 enabling DHCPv6 support explicitly, the DHCPv6 client will be
314 started regardless of the presence of routers on the link, or what
315 flags the routers pass. See "IPv6AcceptRA=".
316 Furthermore, note that by default the domain name specified through
318 DHCP is not used for name resolution. See option UseDomains= below.
319 See the [DHCPv4] or [DHCPv6] sections below for further
321 configuration options for the DHCP client support.
322 DHCPServer=
324 Takes a boolean. If set to "yes", DHCPv4 server will be started.
325 Defaults to "no". Further settings for the DHCP server may be set
326 in the [DHCPServer] section described below.
327 LinkLocalAddressing=
329 Enables link-local address autoconfiguration. Accepts "yes", "no",
330 "ipv4", "ipv6", "fallback", or "ipv4-fallback". If "fallback" or
331 "ipv4-fallback" is specified, then an IPv4 link-local address is
332 configured only when DHCPv4 fails. If "fallback", an IPv6
333 link-local address is always configured, and if "ipv4-fallback",
334 the address is not configured. Note that, the fallback mechanism
335 works only when DHCPv4 client is enabled, that is, it requires
336 "DHCP=yes" or "DHCP=ipv4". If Bridge= is set, defaults to "no", and
337 if not, defaults to "ipv6".
338 IPv6LinkLocalAddressGenerationMode=
340 Specifies how IPv6 link local address is generated. Takes one of
341 "eui64", "none", "stable-privacy" and "random". When unset, the
342 kernel's default will be used. Note that if LinkLocalAdressing= not
343 configured as "ipv6" then IPv6LinkLocalAddressGenerationMode= is
344 ignored.
345 IPv4LLRoute=
347 Takes a boolean. If set to true, sets up the route needed for
348 non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults to
349 false.
350 DefaultRouteOnDevice=
352 Takes a boolean. If set to true, sets up the default route bound to
353 the interface. Defaults to false. This is useful when creating
354 routes on point-to-point interfaces. This is equivalent to e.g. the
355 following.
356 ip route add default dev veth99
358 IPv6Token=
360 Specifies an optional address generation mode and a required IPv6
361 address. If the mode is present, the two parts must be separated
362 with a colon "mode:address". The address generation mode may be
363 either prefixstable or static. If not specified, static is assumed.
364 When the mode is set to static, or unspecified, the lower bits of
366 the supplied address are combined with the upper bits of a prefix
367 received in a Router Advertisement message to form a complete
368 address. Note that if multiple prefixes are received in an RA
369 message, or in multiple RA messages, addresses will be formed from
370 each of them using the supplied address. This mode implements SLAAC
371 but uses a static interface identifier instead of an identifier
372 generated using the EUI-64 algorithm. Because the interface
373 identifier is static, if Duplicate Address Detection detects that
374 the computed address is a duplicate (in use by another node on the
375 link), then this mode will fail to provide an address for that
376 prefix.
377 When the mode is set to "prefixstable" the RFC 7217 algorithm for
379 generating interface identifiers will be used, but only when a
380 prefix received in an RA message matches the supplied address. See
381 RFC 7217[1]. Prefix matching will be attempted against each
382 prefixstable IPv6Token variable provided in the configuration; if a
383 received prefix does not match any of the provided addresses, then
384 the EUI-64 algorithm will be used to form an interface identifier
385 for that prefix. This mode is also SLAAC, but with a potentially
386 stable interface identifier which does not directly map to the
387 interface's hardware address. Note that the prefixstable algorithm
388 includes both the interface's name and MAC address in the hash used
389 to compute the interface identifier, so if either of those are
390 changed the resulting interface identifier (and address) will
391 change, even if the prefix received in the RA message has not
392 changed. Note that if multiple prefixstable IPv6Token variables are
393 supplied with addresses that match a prefix received in an RA
394 message, only the first one will be used to generate addresses.
395 LLMNR=
397 Takes a boolean or "resolve". When true, enables Link-Local
398 Multicast Name Resolution[2] on the link. When set to "resolve",
399 only resolution is enabled, but not host registration and
400 announcement. Defaults to true. This setting is read by systemd-
401 resolved.service(8).
402 MulticastDNS=
404 Takes a boolean or "resolve". When true, enables Multicast DNS[3]
405 support on the link. When set to "resolve", only resolution is
406 enabled, but not host or service registration and announcement.
407 Defaults to false. This setting is read by systemd-
408 resolved.service(8).
409 DNSOverTLS=
411 Takes a boolean or "opportunistic". When true, enables
412 DNS-over-TLS[4] support on the link. When set to "opportunistic",
413 compatibility with non-DNS-over-TLS servers is increased, by
414 automatically turning off DNS-over-TLS servers in this case. This
415 option defines a per-interface setting for resolved.conf(5)'s
416 global DNSOverTLS= option. Defaults to false. This setting is read
417 by systemd-resolved.service(8).
418 DNSSEC=
420 Takes a boolean or "allow-downgrade". When true, enables DNSSEC[5]
421 DNS validation support on the link. When set to "allow-downgrade",
422 compatibility with non-DNSSEC capable networks is increased, by
423 automatically turning off DNSSEC in this case. This option defines
424 a per-interface setting for resolved.conf(5)'s global DNSSEC=
425 option. Defaults to false. This setting is read by systemd-
426 resolved.service(8).
427 DNSSECNegativeTrustAnchors=
429 A space-separated list of DNSSEC negative trust anchor domains. If
430 specified and DNSSEC is enabled, look-ups done via the interface's
431 DNS server will be subject to the list of negative trust anchors,
432 and not require authentication for the specified domains, or
433 anything below it. Use this to disable DNSSEC authentication for
434 specific private domains, that cannot be proven valid using the
435 Internet DNS hierarchy. Defaults to the empty list. This setting is
436 read by systemd-resolved.service(8).
437 LLDP=
439 Controls support for Ethernet LLDP packet reception. LLDP is a
440 link-layer protocol commonly implemented on professional routers
441 and bridges which announces which physical port a system is
442 connected to, as well as other related data. Accepts a boolean or
443 the special value "routers-only". When true, incoming LLDP packets
444 are accepted and a database of all LLDP neighbors maintained. If
445 "routers-only" is set only LLDP data of various types of routers is
446 collected and LLDP data about other types of devices ignored (such
447 as stations, telephones and others). If false, LLDP reception is
448 disabled. Defaults to "routers-only". Use networkctl(1) to query
449 the collected neighbor data. LLDP is only available on Ethernet
450 links. See EmitLLDP= below for enabling LLDP packet emission from
451 the local system.
452 EmitLLDP=
454 Controls support for Ethernet LLDP packet emission. Accepts a
455 boolean parameter or the special values "nearest-bridge",
456 "non-tpmr-bridge" and "customer-bridge". Defaults to false, which
457 turns off LLDP packet emission. If not false, a short LLDP packet
458 with information about the local system is sent out in regular
459 intervals on the link. The LLDP packet will contain information
460 about the local hostname, the local machine ID (as stored in
461 machine-id(5)) and the local interface name, as well as the pretty
462 hostname of the system (as set in machine-info(5)). LLDP emission
463 is only available on Ethernet links. Note that this setting passes
464 data suitable for identification of host to the network and should
465 thus not be enabled on untrusted networks, where such
466 identification data should not be made available. Use this option
467 to permit other systems to identify on which interfaces they are
468 connected to this system. The three special values control
469 propagation of the LLDP packets. The "nearest-bridge" setting
470 permits propagation only to the nearest connected bridge,
471 "non-tpmr-bridge" permits propagation across Two-Port MAC Relays,
472 but not any other bridges, and "customer-bridge" permits
473 propagation until a customer bridge is reached. For details about
474 these concepts, see IEEE 802.1AB-2016[6]. Note that configuring
475 this setting to true is equivalent to "nearest-bridge", the
476 recommended and most restricted level of propagation. See LLDP=
477 above for an option to enable LLDP reception.
478 BindCarrier=
480 A link name or a list of link names. When set, controls the
481 behavior of the current link. When all links in the list are in an
482 operational down state, the current link is brought down. When at
483 least one link has carrier, the current interface is brought up.
484 Address=
486 A static IPv4 or IPv6 address and its prefix length, separated by a
487 "/" character. Specify this key more than once to configure several
488 addresses. The format of the address must be as described in
489 inet_pton(3). This is a short-hand for an [Address] section only
490 containing an Address key (see below). This option may be specified
491 more than once.
492 If the specified address is "0.0.0.0" (for IPv4) or "::" (for
494 IPv6), a new address range of the requested size is automatically
495 allocated from a system-wide pool of unused ranges. Note that the
496 prefix length must be equal or larger than 8 for IPv4, and 64 for
497 IPv6. The allocated range is checked against all current network
498 interfaces and all known network configuration files to avoid
499 address range conflicts. The default system-wide pool consists of
500 192.168.0.0/16, 172.16.0.0/12 and 10.0.0.0/8 for IPv4, and fd00::/8
501 for IPv6. This functionality is useful to manage a large number of
502 dynamically created network interfaces with the same network
503 configuration and automatic address range assignment.
504 Gateway=
506 The gateway address, which must be in the format described in
507 inet_pton(3). This is a short-hand for a [Route] section only
508 containing a Gateway key. This option may be specified more than
509 once.
510 DNS=
512 A DNS server address, which must be in the format described in
513 inet_pton(3). This option may be specified more than once. Each
514 address can optionally take a port number separated with ":", a
515 network interface name or index separated with "%", and a Server
516 Name Indication (SNI) separated with "#". When IPv6 address is
517 specified with a port number, then the address must be in the
518 square brackets. That is, the acceptable full formats are
519 "111.222.333.444:9953%ifname#example.com" for IPv4 and
520 "[1111:2222::3333]:9953%ifname#example.com" for IPv6. This setting
521 can be specified multiple times. If an empty string is assigned,
522 then the all previous assignments are cleared. This setting is read
523 by systemd-resolved.service(8).
524 Domains=
526 A whitespace-separated list of domains which should be resolved
527 using the DNS servers on this link. Each item in the list should be
528 a domain name, optionally prefixed with a tilde ("~"). The domains
529 with the prefix are called "routing-only domains". The domains
530 without the prefix are called "search domains" and are first used
531 as search suffixes for extending single-label hostnames (hostnames
532 containing no dots) to become fully qualified domain names (FQDNs).
533 If a single-label hostname is resolved on this interface, each of
534 the specified search domains are appended to it in turn, converting
535 it into a fully qualified domain name, until one of them may be
536 successfully resolved.
537 Both "search" and "routing-only" domains are used for routing of
539 DNS queries: look-ups for hostnames ending in those domains (hence
540 also single label names, if any "search domains" are listed), are
541 routed to the DNS servers configured for this interface. The domain
542 routing logic is particularly useful on multi-homed hosts with DNS
543 servers serving particular private DNS zones on each interface.
544 The "routing-only" domain "~." (the tilde indicating definition of
546 a routing domain, the dot referring to the DNS root domain which is
547 the implied suffix of all valid DNS names) has special effect. It
548 causes all DNS traffic which does not match another configured
549 domain routing entry to be routed to DNS servers specified for this
550 interface. This setting is useful to prefer a certain set of DNS
551 servers if a link on which they are connected is available.
552 This setting is read by systemd-resolved.service(8). "Search
554 domains" correspond to the domain and search entries in
555 resolv.conf(5). Domain name routing has no equivalent in the
556 traditional glibc API, which has no concept of domain name servers
557 limited to a specific link.
558 DNSDefaultRoute=
560 Takes a boolean argument. If true, this link's configured DNS
561 servers are used for resolving domain names that do not match any
562 link's configured Domains= setting. If false, this link's
563 configured DNS servers are never used for such domains, and are
564 exclusively used for resolving names that match at least one of the
565 domains configured on this link. If not specified defaults to an
566 automatic mode: queries not matching any link's configured domains
567 will be routed to this link if it has no routing-only domains
568 configured.
569 NTP=
571 An NTP server address (either an IP address, or a hostname). This
572 option may be specified more than once. This setting is read by
573 systemd-timesyncd.service(8).
574 IPForward=
576 Configures IP packet forwarding for the system. If enabled,
577 incoming packets on any network interface will be forwarded to any
578 other interfaces according to the routing table. Takes a boolean,
579 or the values "ipv4" or "ipv6", which only enable IP packet
580 forwarding for the specified address family. This controls the
581 net.ipv4.ip_forward and net.ipv6.conf.all.forwarding sysctl options
582 of the network interface (see ip-sysctl.txt[7] for details about
583 sysctl options). Defaults to "no".
584 Note: this setting controls a global kernel option, and does so one
586 way only: if a network that has this setting enabled is set up the
587 global setting is turned on. However, it is never turned off again,
588 even after all networks with this setting enabled are shut down
589 again.
590 To allow IP packet forwarding only between specific network
592 interfaces use a firewall.
593 IPMasquerade=
595 Configures IP masquerading for the network interface. If enabled,
596 packets forwarded from the network interface will be appear as
597 coming from the local host. Takes a boolean argument. Implies
598 IPForward=ipv4. Defaults to "no".
599 IPv6PrivacyExtensions=
601 Configures use of stateless temporary addresses that change over
602 time (see RFC 4941[8], Privacy Extensions for Stateless Address
603 Autoconfiguration in IPv6). Takes a boolean or the special values
604 "prefer-public" and "kernel". When true, enables the privacy
605 extensions and prefers temporary addresses over public addresses.
606 When "prefer-public", enables the privacy extensions, but prefers
607 public addresses over temporary addresses. When false, the privacy
608 extensions remain disabled. When "kernel", the kernel's default
609 setting will be left in place. Defaults to "no".
610 IPv6AcceptRA=
612 Takes a boolean. Controls IPv6 Router Advertisement (RA) reception
613 support for the interface. If true, RAs are accepted; if false, RAs
614 are ignored. When RAs are accepted, they may trigger the start of
615 the DHCPv6 client if the relevant flags are set in the RA data, or
616 if no routers are found on the link. The default is to disable RA
617 reception for bridge devices or when IP forwarding is enabled, and
618 to enable it otherwise. Cannot be enabled on bond devices and when
619 link local addressing is disabled.
620 Further settings for the IPv6 RA support may be configured in the
622 [IPv6AcceptRA] section, see below.
623 Also see ip-sysctl.txt[7] in the kernel documentation regarding
625 "accept_ra", but note that systemd's setting of 1 (i.e. true)
626 corresponds to kernel's setting of 2.
627 Note that kernel's implementation of the IPv6 RA protocol is always
629 disabled, regardless of this setting. If this option is enabled, a
630 userspace implementation of the IPv6 RA protocol is used, and the
631 kernel's own implementation remains disabled, since
632 systemd-networkd needs to know all details supplied in the
633 advertisements, and these are not available from the kernel if the
634 kernel's own implementation is used.
635 IPv6DuplicateAddressDetection=
637 Configures the amount of IPv6 Duplicate Address Detection (DAD)
638 probes to send. When unset, the kernel's default will be used.
639 IPv6HopLimit=
641 Configures IPv6 Hop Limit. For each router that forwards the
642 packet, the hop limit is decremented by 1. When the hop limit field
643 reaches zero, the packet is discarded. When unset, the kernel's
644 default will be used.
645 IPv4AcceptLocal=
647 Takes a boolean. Accept packets with local source addresses. In
648 combination with suitable routing, this can be used to direct
649 packets between two local interfaces over the wire and have them
650 accepted properly. When unset, the kernel's default will be used.
651 IPv4ProxyARP=
653 Takes a boolean. Configures proxy ARP for IPv4. Proxy ARP is the
654 technique in which one host, usually a router, answers ARP requests
655 intended for another machine. By "faking" its identity, the router
656 accepts responsibility for routing packets to the "real"
657 destination. See RFC 1027[9]. When unset, the kernel's default will
658 be used.
659 IPv6ProxyNDP=
661 Takes a boolean. Configures proxy NDP for IPv6. Proxy NDP (Neighbor
662 Discovery Protocol) is a technique for IPv6 to allow routing of
663 addresses to a different destination when peers expect them to be
664 present on a certain physical link. In this case a router answers
665 Neighbour Advertisement messages intended for another machine by
666 offering its own MAC address as destination. Unlike proxy ARP for
667 IPv4, it is not enabled globally, but will only send Neighbour
668 Advertisement messages for addresses in the IPv6 neighbor proxy
669 table, which can also be shown by ip -6 neighbour show proxy.
670 systemd-networkd will control the per-interface `proxy_ndp` switch
671 for each configured interface depending on this option. When unset,
672 the kernel's default will be used.
673 IPv6ProxyNDPAddress=
675 An IPv6 address, for which Neighbour Advertisement messages will be
676 proxied. This option may be specified more than once.
677 systemd-networkd will add the IPv6ProxyNDPAddress= entries to the
678 kernel's IPv6 neighbor proxy table. This option implies
679 IPv6ProxyNDP=yes but has no effect if IPv6ProxyNDP has been set to
680 false. When unset, the kernel's default will be used.
681 IPv6PrefixDelegation=
683 Whether to enable or disable Router Advertisement sending on a
684 link. Allowed values are "static" which distributes prefixes as
685 defined in the [IPv6PrefixDelegation] and any [IPv6Prefix]
686 sections, "dhcpv6" which requests prefixes using a DHCPv6 client
687 configured for another link and any values configured in the
688 [IPv6PrefixDelegation] section while ignoring all static prefix
689 configuration sections, "yes" which uses both static configuration
690 and DHCPv6, and "false" which turns off IPv6 prefix delegation
691 altogether. Defaults to "false". See the [IPv6PrefixDelegation] and
692 the [IPv6Prefix] sections for more configuration options.
693 IPv6MTUBytes=
695 Configures IPv6 maximum transmission unit (MTU). An integer greater
696 than or equal to 1280 bytes. When unset, the kernel's default will
697 be used.
698 Bridge=
700 The name of the bridge to add the link to. See systemd.netdev(5).
701 Bond=
703 The name of the bond to add the link to. See systemd.netdev(5).
704 VRF=
706 The name of the VRF to add the link to. See systemd.netdev(5).
707 VLAN=
709 The name of a VLAN to create on the link. See systemd.netdev(5).
710 This option may be specified more than once.
711 IPVLAN=
713 The name of a IPVLAN to create on the link. See systemd.netdev(5).
714 This option may be specified more than once.
715 MACVLAN=
717 The name of a MACVLAN to create on the link. See systemd.netdev(5).
718 This option may be specified more than once.
719 VXLAN=
721 The name of a VXLAN to create on the link. See systemd.netdev(5).
722 This option may be specified more than once.
723 Tunnel=
725 The name of a Tunnel to create on the link. See systemd.netdev(5).
726 This option may be specified more than once.
727 MACsec=
729 The name of a MACsec device to create on the link. See
730 systemd.netdev(5). This option may be specified more than once.
731 ActiveSlave=
733 Takes a boolean. Specifies the new active slave. The "ActiveSlave="
734 option is only valid for following modes: "active-backup",
735 "balance-alb" and "balance-tlb". Defaults to false.
736 PrimarySlave=
738 Takes a boolean. Specifies which slave is the primary device. The
739 specified device will always be the active slave while it is
740 available. Only when the primary is off-line will alternate devices
741 be used. This is useful when one slave is preferred over another,
742 e.g. when one slave has higher throughput than another. The
743 "PrimarySlave=" option is only valid for following modes:
744 "active-backup", "balance-alb" and "balance-tlb". Defaults to
745 false.
746 ConfigureWithoutCarrier=
748 Takes a boolean. Allows networkd to configure a specific link even
749 if it has no carrier. Defaults to false. If IgnoreCarrierLoss= is
750 not explicitly set, it will default to this value.
751 IgnoreCarrierLoss=
753 Takes a boolean. Allows networkd to retain both the static and
754 dynamic configuration of the interface even if its carrier is lost.
755 When unset, the value specified with ConfigureWithoutCarrier= is
756 used.
757 Xfrm=
759 The name of the xfrm to create on the link. See systemd.netdev(5).
760 This option may be specified more than once.
761 KeepConfiguration=
763 Takes a boolean or one of "static", "dhcp-on-stop", "dhcp". When
764 "static", systemd-networkd will not drop static addresses and
765 routes on starting up process. When set to "dhcp-on-stop",
766 systemd-networkd will not drop addresses and routes on stopping the
767 daemon. When "dhcp", the addresses and routes provided by a DHCP
768 server will never be dropped even if the DHCP lease expires. This
769 is contrary to the DHCP specification, but may be the best choice
770 if, e.g., the root filesystem relies on this connection. The
771 setting "dhcp" implies "dhcp-on-stop", and "yes" implies "dhcp" and
772 "static". Defaults to "no".
773
775 An [Address] section accepts the following keys. Specify several
776 [Address] sections to configure several addresses.
777 Address=
779 As in the [Network] section. This key is mandatory. Each [Address]
780 section can contain one Address= setting.
781 Peer=
783 The peer address in a point-to-point connection. Accepts the same
784 format as the Address= key.
785 Broadcast=
787 The broadcast address, which must be in the format described in
788 inet_pton(3). This key only applies to IPv4 addresses. If it is not
789 given, it is derived from the Address= key.
790 Label=
792 An address label.
793 PreferredLifetime=
795 Allows the default "preferred lifetime" of the address to be
796 overridden. Only three settings are accepted: "forever" or
797 "infinity" which is the default and means that the address never
798 expires, and "0" which means that the address is considered
799 immediately "expired" and will not be used, unless explicitly
800 requested. A setting of PreferredLifetime=0 is useful for addresses
801 which are added to be used only by a specific application, which is
802 then configured to use them explicitly.
803 Scope=
805 The scope of the address, which can be "global", "link" or "host"
806 or an unsigned integer in the range 0—255. Defaults to "global".
807 HomeAddress=
809 Takes a boolean. Designates this address the "home address" as
810 defined in RFC 6275[10]. Supported only on IPv6. Defaults to false.
811 DuplicateAddressDetection=
813 Takes one of "ipv4", "ipv6", "both", "none". When "ipv4", performs
814 IPv4 Duplicate Address Detection. See RFC 5224[11]. When "ipv6",
815 performs IPv6 Duplicate Address Detection. See RFC 4862[12].
816 Defaults to "ipv6".
817 ManageTemporaryAddress=
819 Takes a boolean. If true the kernel manage temporary addresses
820 created from this one as template on behalf of Privacy Extensions
821 RFC 3041[13]. For this to become active, the use_tempaddr sysctl
822 setting has to be set to a value greater than zero. The given
823 address needs to have a prefix length of 64. This flag allows using
824 privacy extensions in a manually configured network, just like if
825 stateless auto-configuration was active. Defaults to false.
826 AddPrefixRoute=
828 Takes a boolean. When true, the prefix route for the address is
829 automatically added. Defaults to true.
830 AutoJoin=
832 Takes a boolean. Joining multicast group on ethernet level via ip
833 maddr command would not work if we have an Ethernet switch that
834 does IGMP snooping since the switch would not replicate multicast
835 packets on ports that did not have IGMP reports for the multicast
836 addresses. Linux vxlan interfaces created via ip link add vxlan or
837 networkd's netdev kind vxlan have the group option that enables
838 then to do the required join. By extending ip address command with
839 option "autojoin" we can get similar functionality for openvswitch
840 (OVS) vxlan interfaces as well as other tunneling mechanisms that
841 need to receive multicast traffic. Defaults to "no".
842
844 A [Neighbor] section accepts the following keys. The neighbor section
845 adds a permanent, static entry to the neighbor table (IPv6) or ARP
846 table (IPv4) for the given hardware address on the links matched for
847 the network. Specify several [Neighbor] sections to configure several
848 static neighbors.
849 Address=
851 The IP address of the neighbor.
852 LinkLayerAddress=
854 The link layer address (MAC address or IP address) of the neighbor.
855
857 An [IPv6AddressLabel] section accepts the following keys. Specify
858 several [IPv6AddressLabel] sections to configure several address
859 labels. IPv6 address labels are used for address selection. See RFC
860 3484[14]. Precedence is managed by userspace, and only the label itself
861 is stored in the kernel.
862 Label=
864 The label for the prefix, an unsigned integer in the range
865 0–4294967294. 0xffffffff is reserved. This setting is mandatory.
866 Prefix=
868 IPv6 prefix is an address with a prefix length, separated by a
869 slash "/" character. This key is mandatory.
870
872 An [RoutingPolicyRule] section accepts the following keys. Specify
873 several [RoutingPolicyRule] sections to configure several rules.
874 TypeOfService=
876 Takes a number between 0 and 255 that specifies the type of service
877 to match.
878 From=
880 Specifies the source address prefix to match. Possibly followed by
881 a slash and the prefix length.
882 To=
884 Specifies the destination address prefix to match. Possibly
885 followed by a slash and the prefix length.
886 FirewallMark=
888 Specifies the iptables firewall mark value to match (a number
889 between 1 and 4294967295).
890 Table=
892 Specifies the routing table identifier to lookup if the rule
893 selector matches. Takes one of "default", "main", and "local", or a
894 number between 1 and 4294967295. Defaults to "main".
895 Priority=
897 Specifies the priority of this rule. Priority= is an unsigned
898 integer. Higher number means lower priority, and rules get
899 processed in order of increasing number.
900 IncomingInterface=
902 Specifies incoming device to match. If the interface is loopback,
903 the rule only matches packets originating from this host.
904 OutgoingInterface=
906 Specifies the outgoing device to match. The outgoing interface is
907 only available for packets originating from local sockets that are
908 bound to a device.
909 SourcePort=
911 Specifies the source IP port or IP port range match in forwarding
912 information base (FIB) rules. A port range is specified by the
913 lower and upper port separated by a dash. Defaults to unset.
914 DestinationPort=
916 Specifies the destination IP port or IP port range match in
917 forwarding information base (FIB) rules. A port range is specified
918 by the lower and upper port separated by a dash. Defaults to unset.
919 IPProtocol=
921 Specifies the IP protocol to match in forwarding information base
922 (FIB) rules. Takes IP protocol name such as "tcp", "udp" or "sctp",
923 or IP protocol number such as "6" for "tcp" or "17" for "udp".
924 Defaults to unset.
925 InvertRule=
927 A boolean. Specifies whether the rule is to be inverted. Defaults
928 to false.
929 Family=
931 Takes a special value "ipv4", "ipv6", or "both". By default, the
932 address family is determined by the address specified in To= or
933 From=. If neither To= nor From= are specified, then defaults to
934 "ipv4".
935 User=
937 Takes a username, a user ID, or a range of user IDs separated by a
938 dash. Defaults to unset.
939 SuppressPrefixLength=
941 Takes a number N in the range 0-128 and rejects routing decisions
942 that have a prefix length of N or less. Defaults to unset.
943
945 The [NextHop] section is used to manipulate entries in the kernel's
946 "nexthop" tables. The [NextHop] section accepts the following keys.
947 Specify several [NextHop] sections to configure several hops.
948 Gateway=
950 As in the [Network] section. This is mandatory.
951 Id=
953 The id of the nexthop (an unsigned integer). If unspecified or '0'
954 then automatically chosen by kernel.
955
957 The [Route] section accepts the following keys. Specify several [Route]
958 sections to configure several routes.
959 Gateway=
961 Takes the gateway address or special value "_dhcp". If "_dhcp",
962 then the gateway address provided by DHCP (or in the IPv6 case,
963 provided by IPv6 RA) is used.
964 GatewayOnLink=
966 Takes a boolean. If set to true, the kernel does not have to check
967 if the gateway is reachable directly by the current machine (i.e.,
968 the kernel does not need to check if the gateway is attached to the
969 local network), so that we can insert the route in the kernel table
970 without it being complained about. Defaults to "no".
971 Destination=
973 The destination prefix of the route. Possibly followed by a slash
974 and the prefix length. If omitted, a full-length host route is
975 assumed.
976 Source=
978 The source prefix of the route. Possibly followed by a slash and
979 the prefix length. If omitted, a full-length host route is assumed.
980 Metric=
982 The metric of the route (an unsigned integer).
983 IPv6Preference=
985 Specifies the route preference as defined in RFC 4191[15] for
986 Router Discovery messages. Which can be one of "low" the route has
987 a lowest priority, "medium" the route has a default priority or
988 "high" the route has a highest priority.
989 Scope=
991 The scope of the route, which can be "global", "site", "link",
992 "host", or "nowhere". For IPv4 route, defaults to "host" if Type=
993 is "local" or "nat", and "link" if Type= is "broadcast",
994 "multicast", or "anycast". In other cases, defaults to "global".
995 PreferredSource=
997 The preferred source address of the route. The address must be in
998 the format described in inet_pton(3).
999 Table=
1001 The table identifier for the route. Takes "default", "main",
1002 "local" or a number between 1 and 4294967295. The table can be
1003 retrieved using ip route show table num. If unset and Type= is
1004 "local", "broadcast", "anycast", or "nat", then "local" is used. In
1005 other cases, defaults to "main".
1006 Protocol=
1008 The protocol identifier for the route. Takes a number between 0 and
1009 255 or the special values "kernel", "boot", "static", "ra" and
1010 "dhcp". Defaults to "static".
1011 Type=
1013 Specifies the type for the route. Takes one of "unicast", "local",
1014 "broadcast", "anycast", "multicast", "blackhole", "unreachable",
1015 "prohibit", "throw", "nat", and "xresolve". If "unicast", a regular
1016 route is defined, i.e. a route indicating the path to take to a
1017 destination network address. If "blackhole", packets to the defined
1018 route are discarded silently. If "unreachable", packets to the
1019 defined route are discarded and the ICMP message "Host Unreachable"
1020 is generated. If "prohibit", packets to the defined route are
1021 discarded and the ICMP message "Communication Administratively
1022 Prohibited" is generated. If "throw", route lookup in the current
1023 routing table will fail and the route selection process will return
1024 to Routing Policy Database (RPDB). Defaults to "unicast".
1025 InitialCongestionWindow=
1027 The TCP initial congestion window is used during the start of a TCP
1028 connection. During the start of a TCP session, when a client
1029 requests a resource, the server's initial congestion window
1030 determines how many data bytes will be sent during the initial
1031 burst of data. Takes a size in bytes between 1 and 4294967295 (2^32
1032 - 1). The usual suffixes K, M, G are supported and are understood
1033 to the base of 1024. When unset, the kernel's default will be used.
1034 InitialAdvertisedReceiveWindow=
1036 The TCP initial advertised receive window is the amount of receive
1037 data (in bytes) that can initially be buffered at one time on a
1038 connection. The sending host can send only that amount of data
1039 before waiting for an acknowledgment and window update from the
1040 receiving host. Takes a size in bytes between 1 and 4294967295
1041 (2^32 - 1). The usual suffixes K, M, G are supported and are
1042 understood to the base of 1024. When unset, the kernel's default
1043 will be used.
1044 QuickAck=
1046 Takes a boolean. When true enables TCP quick ack mode for the
1047 route. When unset, the kernel's default will be used.
1048 FastOpenNoCookie=
1050 Takes a boolean. When true enables TCP fastopen without a cookie on
1051 a per-route basis. When unset, the kernel's default will be used.
1052 TTLPropagate=
1054 Takes a boolean. When true enables TTL propagation at Label
1055 Switched Path (LSP) egress. When unset, the kernel's default will
1056 be used.
1057 MTUBytes=
1059 The maximum transmission unit in bytes to set for the route. The
1060 usual suffixes K, M, G, are supported and are understood to the
1061 base of 1024.
1062 Note that if IPv6 is enabled on the interface, and the MTU is
1064 chosen below 1280 (the minimum MTU for IPv6) it will automatically
1065 be increased to this value.
1066 IPServiceType=
1068 Takes string; "CS6" or "CS4". Used to set IP service type to CS6
1069 (network control) or CS4 (Realtime). Defaults to CS6.
1070 MultiPathRoute=address[@name] [weight]
1072 Configures multipath route. Multipath routing is the technique of
1073 using multiple alternative paths through a network. Takes gateway
1074 address. Optionally, takes a network interface name or index
1075 separated with "@", and a weight in 1..256 for this multipath route
1076 separated with whitespace. This setting can be specified multiple
1077 times. If an empty string is assigned, then the all previous
1078 assignments are cleared.
1079
1081 The [DHCPv4] section configures the DHCPv4 client, if it is enabled
1082 with the DHCP= setting described above:
1083 UseDNS=
1085 When true (the default), the DNS servers received from the DHCP
1086 server will be used.
1087 This corresponds to the nameserver option in resolv.conf(5).
1089 RoutesToDNS=
1091 When true, the routes to the DNS servers received from the DHCP
1092 server will be configured. When UseDNS= is disabled, this setting
1093 is ignored. Defaults to false.
1094 UseNTP=
1096 When true (the default), the NTP servers received from the DHCP
1097 server will be used by systemd-timesyncd.service.
1098 UseSIP=
1100 When true (the default), the SIP servers received from the DHCP
1101 server will be collected and made available to client programs.
1102 UseMTU=
1104 When true, the interface maximum transmission unit from the DHCP
1105 server will be used on the current link. If MTUBytes= is set, then
1106 this setting is ignored. Defaults to false.
1107 Anonymize=
1109 Takes a boolean. When true, the options sent to the DHCP server
1110 will follow the RFC 7844[16] (Anonymity Profiles for DHCP Clients)
1111 to minimize disclosure of identifying information. Defaults to
1112 false.
1113 This option should only be set to true when MACAddressPolicy= is
1115 set to "random" (see systemd.link(5)).
1116 Note that this configuration will overwrite others. In concrete,
1118 the following variables will be ignored: SendHostname=,
1119 ClientIdentifier=, UseRoutes=, UseMTU=, VendorClassIdentifier=,
1120 UseTimezone=.
1121 With this option enabled DHCP requests will mimic those generated
1123 by Microsoft Windows, in order to reduce the ability to fingerprint
1124 and recognize installations. This means DHCP request sizes will
1125 grow and lease data will be more comprehensive than normally,
1126 though most of the requested data is not actually used.
1127 SendHostname=
1129 When true (the default), the machine's hostname will be sent to the
1130 DHCP server. Note that the machine's hostname must consist only of
1131 7-bit ASCII lower-case characters and no spaces or dots, and be
1132 formatted as a valid DNS domain name. Otherwise, the hostname is
1133 not sent even if this is set to true.
1134 MUDURL=
1136 When configured, the Manufacturer Usage Descriptions (MUD) URL will
1137 be sent to the DHCPv4 server. Takes an URL of length up to 255
1138 characters. A superficial verification that the string is a valid
1139 URL will be performed. DHCPv4 clients are intended to have at most
1140 one MUD URL associated with them. See RFC 8520[17].
1141 UseHostname=
1143 When true (the default), the hostname received from the DHCP server
1144 will be set as the transient hostname of the system.
1145 Hostname=
1147 Use this value for the hostname which is sent to the DHCP server,
1148 instead of machine's hostname. Note that the specified hostname
1149 must consist only of 7-bit ASCII lower-case characters and no
1150 spaces or dots, and be formatted as a valid DNS domain name.
1151 UseDomains=
1153 Takes a boolean, or the special value "route". When true, the
1154 domain name received from the DHCP server will be used as DNS
1155 search domain over this link, similar to the effect of the Domains=
1156 setting. If set to "route", the domain name received from the DHCP
1157 server will be used for routing DNS queries only, but not for
1158 searching, similar to the effect of the Domains= setting when the
1159 argument is prefixed with "~". Defaults to false.
1160 It is recommended to enable this option only on trusted networks,
1162 as setting this affects resolution of all hostnames, in particular
1163 of single-label names. It is generally safer to use the supplied
1164 domain only as routing domain, rather than as search domain, in
1165 order to not have it affect local resolution of single-label names.
1166 When set to true, this setting corresponds to the domain option in
1168 resolv.conf(5).
1169 UseRoutes=
1171 When true (the default), the static routes will be requested from
1172 the DHCP server and added to the routing table with a metric of
1173 1024, and a scope of "global", "link" or "host", depending on the
1174 route's destination and gateway. If the destination is on the local
1175 host, e.g., 127.x.x.x, or the same as the link's own address, the
1176 scope will be set to "host". Otherwise if the gateway is null (a
1177 direct route), a "link" scope will be used. For anything else,
1178 scope defaults to "global".
1179 UseGateway=
1181 When true, the gateway will be requested from the DHCP server and
1182 added to the routing table with a metric of 1024, and a scope of
1183 "link". When unset, the value specified with UseRoutes= is used.
1184 UseTimezone=
1186 When true, the timezone received from the DHCP server will be set
1187 as timezone of the local system. Defaults to "no".
1188 ClientIdentifier=
1190 The DHCPv4 client identifier to use. Takes one of "mac", "duid" or
1191 "duid-only". If set to "mac", the MAC address of the link is used.
1192 If set to "duid", an RFC4361-compliant Client ID, which is the
1193 combination of IAID and DUID (see below), is used. If set to
1194 "duid-only", only DUID is used, this may not be RFC compliant, but
1195 some setups may require to use this. Defaults to "duid".
1196 VendorClassIdentifier=
1198 The vendor class identifier used to identify vendor type and
1199 configuration.
1200 UserClass=
1202 A DHCPv4 client can use UserClass option to identify the type or
1203 category of user or applications it represents. The information
1204 contained in this option is a string that represents the user class
1205 of which the client is a member. Each class sets an identifying
1206 string of information to be used by the DHCP service to classify
1207 clients. Takes a whitespace-separated list of strings.
1208 MaxAttempts=
1210 Specifies how many times the DHCPv4 client configuration should be
1211 attempted. Takes a number or "infinity". Defaults to "infinity".
1212 Note that the time between retries is increased exponentially, so
1213 the network will not be overloaded even if this number is high.
1214 DUIDType=
1216 Override the global DUIDType setting for this network. See
1217 networkd.conf(5) for a description of possible values.
1218 DUIDRawData=
1220 Override the global DUIDRawData setting for this network. See
1221 networkd.conf(5) for a description of possible values.
1222 IAID=
1224 The DHCP Identity Association Identifier (IAID) for the interface,
1225 a 32-bit unsigned integer.
1226 RequestBroadcast=
1228 Request the server to use broadcast messages before the IP address
1229 has been configured. This is necessary for devices that cannot
1230 receive RAW packets, or that cannot receive packets at all before
1231 an IP address has been configured. On the other hand, this must not
1232 be enabled on networks where broadcasts are filtered out.
1233 RouteMetric=
1235 Set the routing metric for routes specified by the DHCP server.
1236 Defaults to 1024.
1237 RouteTable=num
1239 The table identifier for DHCP routes (a number between 1 and
1240 4294967295, or 0 to unset). The table can be retrieved using ip
1241 route show table num.
1242 When used in combination with VRF=, the VRF's routing table is used
1244 when this parameter is not specified.
1245 RouteMTUBytes=
1247 Specifies the MTU for the DHCP routes. Please see the [Route]
1248 section for further details.
1249 ListenPort=
1251 Allow setting custom port for the DHCP client to listen on.
1252 FallbackLeaseLifetimeSec=
1254 Allows to set DHCPv4 lease lifetime when DHCPv4 server does not
1255 send the lease lifetime. Takes one of "forever" or "infinity" means
1256 that the address never expires. Defaults to unset.
1257 SendRelease=
1259 When true, the DHCPv4 client sends a DHCP release packet when it
1260 stops. Defaults to true.
1261 SendDecline=
1263 A boolean. When "true", the DHCPv4 client receives the IP address
1264 from the DHCP server. After a new IP is received, the DHCPv4 client
1265 performs IPv4 Duplicate Address Detection. If duplicate use is
1266 detected, the DHCPv4 client rejects the IP by sending a DHCPDECLINE
1267 packet and tries to obtain an IP address again. See RFC 5224[11].
1268 Defaults to "unset".
1269 DenyList=
1271 A whitespace-separated list of IPv4 addresses. DHCP offers from
1272 servers in the list are rejected. Note that if AllowList= is
1273 configured then DenyList= is ignored.
1274 AllowList=
1276 A whitespace-separated list of IPv4 addresses. DHCP offers from
1277 servers in the list are accepted.
1278 RequestOptions=
1280 When configured, allows to set arbitrary request options in the
1281 DHCPv4 request options list and will be sent to the DHCPV4 server.
1282 A whitespace-separated list of integers in the range 1..254.
1283 Defaults to unset.
1284 SendOption=
1286 Send an arbitrary raw option in the DHCPv4 request. Takes a DHCP
1287 option number, data type and data separated with a colon
1288 ("option:type:value"). The option number must be an integer in the
1289 range 1..254. The type takes one of "uint8", "uint16", "uint32",
1290 "ipv4address", or "string". Special characters in the data string
1291 may be escaped using C-style escapes[18]. This setting can be
1292 specified multiple times. If an empty string is specified, then all
1293 options specified earlier are cleared. Defaults to unset.
1294 SendVendorOption=
1296 Send an arbitrary vendor option in the DHCPv4 request. Takes a DHCP
1297 option number, data type and data separated with a colon
1298 ("option:type:value"). The option number must be an integer in the
1299 range 1..254. The type takes one of "uint8", "uint16", "uint32",
1300 "ipv4address", or "string". Special characters in the data string
1301 may be escaped using C-style escapes[18]. This setting can be
1302 specified multiple times. If an empty string is specified, then all
1303 options specified earlier are cleared. Defaults to unset.
1304
1306 The [DHCPv6] section configures the DHCPv6 client, if it is enabled
1307 with the DHCP= setting described above, or invoked by the IPv6 Router
1308 Advertisement:
1309 UseDNS=, UseNTP=
1311 As in the [DHCPv4] section.
1312 RouteMetric=
1314 Set the routing metric for routes specified by the DHCP server.
1315 Defaults to 1024.
1316 RapidCommit=
1318 Takes a boolean. The DHCPv6 client can obtain configuration
1319 parameters from a DHCPv6 server through a rapid two-message
1320 exchange (solicit and reply). When the rapid commit option is
1321 enabled by both the DHCPv6 client and the DHCPv6 server, the
1322 two-message exchange is used, rather than the default four-message
1323 exchange (solicit, advertise, request, and reply). The two-message
1324 exchange provides faster client configuration and is beneficial in
1325 environments in which networks are under a heavy load. See RFC
1326 3315[19] for details. Defaults to true.
1327 MUDURL=
1329 When configured, the Manufacturer Usage Descriptions (MUD) URL will
1330 be sent to the DHCPV6 server. Takes an URL of length up to 255
1331 characters. A superficial verification that the string is a valid
1332 URL will be performed. DHCPv6 clients are intended to have at most
1333 one MUD URL associated with them. See RFC 8520[17].
1334 RequestOptions=
1336 When configured, allows to set arbitrary request options in the
1337 DHCPv6 request options list and will sent to the DHCPV6 server. A
1338 whitespace-separated list of integers in the range 1..254. Defaults
1339 to unset.
1340 SendVendorOption=
1342 Send an arbitrary vendor option in the DHCPv6 request. Takes an
1343 enterprise identifier, DHCP option number, data type, and data
1344 separated with a colon ("enterprise identifier:option:type:
1345 value"). Enterprise identifier is an unsigned integer in the range
1346 1–4294967294. The option number must be an integer in the range
1347 1–254. Data type takes one of "uint8", "uint16", "uint32",
1348 "ipv4address", "ipv6address", or "string". Special characters in
1349 the data string may be escaped using C-style escapes[18]. This
1350 setting can be specified multiple times. If an empty string is
1351 specified, then all options specified earlier are cleared. Defaults
1352 to unset.
1353 ForceDHCPv6PDOtherInformation=
1355 Takes a boolean that enforces DHCPv6 stateful mode when the 'Other
1356 information' bit is set in Router Advertisement messages. By
1357 default setting only the 'O' bit in Router Advertisements makes
1358 DHCPv6 request network information in a stateless manner using a
1359 two-message Information Request and Information Reply message
1360 exchange. RFC 7084[20], requirement WPD-4, updates this behavior
1361 for a Customer Edge router so that stateful DHCPv6 Prefix
1362 Delegation is also requested when only the 'O' bit is set in Router
1363 Advertisements. This option enables such a CE behavior as it is
1364 impossible to automatically distinguish the intention of the 'O'
1365 bit otherwise. By default this option is set to 'false', enable it
1366 if no prefixes are delegated when the device should be acting as a
1367 CE router.
1368 PrefixDelegationHint=
1370 Takes an IPv6 address with prefix length in the same format as the
1371 Address= in the [Network] section. The DHCPv6 client will include a
1372 prefix hint in the DHCPv6 solicitation sent to the server. The
1373 prefix length must be in the range 1–128. Defaults to unset.
1374 WithoutRA=
1376 Allows DHCPv6 client to start without router advertisements's
1377 managed or other address configuration flag. Takes one of "solicit"
1378 or "information-request". Defaults to unset.
1379 SendOption=
1381 As in the [DHCPv4] section, however because DHCPv6 uses 16-bit
1382 fields to store option numbers, the option number is an integer in
1383 the range 1..65536.
1384 UserClass=
1386 A DHCPv6 client can use User Class option to identify the type or
1387 category of user or applications it represents. The information
1388 contained in this option is a string that represents the user class
1389 of which the client is a member. Each class sets an identifying
1390 string of information to be used by the DHCP service to classify
1391 clients. Special characters in the data string may be escaped using
1392 C-style escapes[18]. This setting can be specified multiple times.
1393 If an empty string is specified, then all options specified earlier
1394 are cleared. Takes a whitespace-separated list of strings. Note
1395 that currently NUL bytes are not allowed.
1396 VendorClass=
1398 A DHCPv6 client can use VendorClass option to identify the vendor
1399 that manufactured the hardware on which the client is running. The
1400 information contained in the data area of this option is contained
1401 in one or more opaque fields that identify details of the hardware
1402 configuration. Takes a whitespace-separated list of strings.
1403
1405 The [DHCPv6PrefixDelegation] section configures delegated prefix
1406 assigned by DHCPv6 server. The settings in this section are used only
1407 when IPv6PrefixDelegation= setting is enabled, or set to "dhcpv6".
1408 SubnetId=
1410 Configure a specific subnet ID on the interface from a (previously)
1411 received prefix delegation. You can either set "auto" (the default)
1412 or a specific subnet ID (as defined in RFC 4291[21], section
1413 2.5.4), in which case the allowed value is hexadecimal, from 0 to
1414 0x7fffffffffffffff inclusive. This option is only effective when
1415 used together with IPv6PrefixDelegation= and the corresponding
1416 configuration on the upstream interface.
1417 Assign=
1419 Takes a boolean. Specifies whether to add an address from the
1420 delegated prefixes which are received from the WAN interface by the
1421 IPv6PrefixDelegation=. When true (on LAN interfce), the EUI-64
1422 algorithm will be used to form an interface identifier from the
1423 delegated prefixes. Defaults to true.
1424 Token=
1426 Specifies an optional address generation mode for Assign=. Takes an
1427 IPv6 address. When set, the lower bits of the supplied address are
1428 combined with the upper bits of a delegatad prefix received from
1429 the WAN interface by the IPv6PrefixDelegation= prefixes to form a
1430 complete address.
1431
1433 The [IPv6AcceptRA] section configures the IPv6 Router Advertisement
1434 (RA) client, if it is enabled with the IPv6AcceptRA= setting described
1435 above:
1436 UseDNS=
1438 When true (the default), the DNS servers received in the Router
1439 Advertisement will be used.
1440 This corresponds to the nameserver option in resolv.conf(5).
1442 UseDomains=
1444 Takes a boolean, or the special value "route". When true, the
1445 domain name received via IPv6 Router Advertisement (RA) will be
1446 used as DNS search domain over this link, similar to the effect of
1447 the Domains= setting. If set to "route", the domain name received
1448 via IPv6 RA will be used for routing DNS queries only, but not for
1449 searching, similar to the effect of the Domains= setting when the
1450 argument is prefixed with "~". Defaults to false.
1451 It is recommended to enable this option only on trusted networks,
1453 as setting this affects resolution of all hostnames, in particular
1454 of single-label names. It is generally safer to use the supplied
1455 domain only as routing domain, rather than as search domain, in
1456 order to not have it affect local resolution of single-label names.
1457 When set to true, this setting corresponds to the domain option in
1459 resolv.conf(5).
1460 RouteTable=num
1462 The table identifier for the routes received in the Router
1463 Advertisement (a number between 1 and 4294967295, or 0 to unset).
1464 The table can be retrieved using ip route show table num.
1465 UseAutonomousPrefix=
1467 When true (the default), the autonomous prefix received in the
1468 Router Advertisement will be used and take precedence over any
1469 statically configured ones.
1470 UseOnLinkPrefix=
1472 When true (the default), the onlink prefix received in the Router
1473 Advertisement will be used and take precedence over any statically
1474 configured ones.
1475 DenyList=
1477 A whitespace-separated list of IPv6 prefixes. IPv6 prefixes
1478 supplied via router advertisements in the list are ignored.
1479 DHCPv6Client=
1481 Takes a boolean, or the special value "always". When true or
1482 "always", the DHCPv6 client will be started when the RA has the
1483 managed or other information flag. If set to "always", the DHCPv6
1484 client will also be started in managed mode when neither managed
1485 nor other information flag is set in the RA. Defaults to true.
1486
1488 The [DHCPServer] section contains settings for the DHCP server, if
1489 enabled via the DHCPServer= option described above:
1490 PoolOffset=, PoolSize=
1492 Configures the pool of addresses to hand out. The pool is a
1493 contiguous sequence of IP addresses in the subnet configured for
1494 the server address, which does not include the subnet nor the
1495 broadcast address. PoolOffset= takes the offset of the pool from
1496 the start of subnet, or zero to use the default value. PoolSize=
1497 takes the number of IP addresses in the pool or zero to use the
1498 default value. By default, the pool starts at the first address
1499 after the subnet address and takes up the rest of the subnet,
1500 excluding the broadcast address. If the pool includes the server
1501 address (the default), this is reserved and not handed out to
1502 clients.
1503 DefaultLeaseTimeSec=, MaxLeaseTimeSec=
1505 Control the default and maximum DHCP lease time to pass to clients.
1506 These settings take time values in seconds or another common time
1507 unit, depending on the suffix. The default lease time is used for
1508 clients that did not ask for a specific lease time. If a client
1509 asks for a lease time longer than the maximum lease time, it is
1510 automatically shortened to the specified time. The default lease
1511 time defaults to 1h, the maximum lease time to 12h. Shorter lease
1512 times are beneficial if the configuration data in DHCP leases
1513 changes frequently and clients shall learn the new settings with
1514 shorter latencies. Longer lease times reduce the generated DHCP
1515 network traffic.
1516 EmitDNS=, DNS=
1518 EmitDNS= takes a boolean. Configures whether the DHCP leases handed
1519 out to clients shall contain DNS server information. Defaults to
1520 "yes". The DNS servers to pass to clients may be configured with
1521 the DNS= option, which takes a list of IPv4 addresses. If the
1522 EmitDNS= option is enabled but no servers configured, the servers
1523 are automatically propagated from an "uplink" interface that has
1524 appropriate servers set. The "uplink" interface is determined by
1525 the default route of the system with the highest priority. Note
1526 that this information is acquired at the time the lease is handed
1527 out, and does not take uplink interfaces into account that acquire
1528 DNS server information at a later point. If no suitable uplinkg
1529 interface is found the DNS server data from /etc/resolv.conf is
1530 used. Also, note that the leases are not refreshed if the uplink
1531 network configuration changes. To ensure clients regularly acquire
1532 the most current uplink DNS server information, it is thus
1533 advisable to shorten the DHCP lease time via MaxLeaseTimeSec=
1534 described above.
1535 EmitNTP=, NTP=, EmitSIP=, SIP=, EmitPOP3=, POP3=, EmitSMTP=, SMTP=,
1537 EmitLPR=, LPR=
1538 Similar to the EmitDNS= and DNS= settings described above, these
1539 settings configure whether and what server information for the
1540 indicate protocol shall be emitted as part of the DHCP lease. The
1541 same syntax, propagation semantics and defaults apply as for
1542 EmitDNS= and DNS=.
1543 EmitRouter=
1545 Similar to the EmitDNS= setting described above, this setting
1546 configures whether the DHCP lease should contain the router option.
1547 The same syntax, propagation semantics and defaults apply as for
1548 EmitDNS=.
1549 EmitTimezone=, Timezone=
1551 Takes a boolean. Configures whether the DHCP leases handed out to
1552 clients shall contain timezone information. Defaults to "yes". The
1553 Timezone= setting takes a timezone string (such as "Europe/Berlin"
1554 or "UTC") to pass to clients. If no explicit timezone is set, the
1555 system timezone of the local host is propagated, as determined by
1556 the /etc/localtime symlink.
1557 SendOption=
1559 Send a raw option with value via DHCPv4 server. Takes a DHCP option
1560 number, data type and data ("option:type:value"). The option number
1561 is an integer in the range 1..254. The type takes one of "uint8",
1562 "uint16", "uint32", "ipv4address", "ipv6address", or "string".
1563 Special characters in the data string may be escaped using C-style
1564 escapes[18]. This setting can be specified multiple times. If an
1565 empty string is specified, then all options specified earlier are
1566 cleared. Defaults to unset.
1567 SendVendorOption=
1569 Send a vendor option with value via DHCPv4 server. Takes a DHCP
1570 option number, data type and data ("option:type:value"). The option
1571 number is an integer in the range 1..254. The type takes one of
1572 "uint8", "uint16", "uint32", "ipv4address", or "string". Special
1573 characters in the data string may be escaped using C-style
1574 escapes[18]. This setting can be specified multiple times. If an
1575 empty string is specified, then all options specified earlier are
1576 cleared. Defaults to unset.
1577
1579 The [IPv6PrefixDelegation] section contains settings for sending IPv6
1580 Router Advertisements and whether to act as a router, if enabled via
1581 the IPv6PrefixDelegation= option described above. IPv6 network prefixes
1582 are defined with one or more [IPv6Prefix] sections.
1583 Managed=, OtherInformation=
1585 Takes a boolean. Controls whether a DHCPv6 server is used to
1586 acquire IPv6 addresses on the network link when Managed= is set to
1587 "true" or if only additional network information can be obtained
1588 via DHCPv6 for the network link when OtherInformation= is set to
1589 "true". Both settings default to "false", which means that a DHCPv6
1590 server is not being used.
1591 RouterLifetimeSec=
1593 Takes a timespan. Configures the IPv6 router lifetime in seconds.
1594 When set to 0, the host is not acting as a router. Defaults to 30
1595 minutes.
1596 RouterPreference=
1598 Configures IPv6 router preference if RouterLifetimeSec= is
1599 non-zero. Valid values are "high", "medium" and "low", with
1600 "normal" and "default" added as synonyms for "medium" just to make
1601 configuration easier. See RFC 4191[15] for details. Defaults to
1602 "medium".
1603 EmitDNS=, DNS=
1605 DNS= specifies a list of recursive DNS server IPv6 addresses that
1606 are distributed via Router Advertisement messages when EmitDNS= is
1607 true. DNS= also takes special value "_link_local"; in that case
1608 the IPv6 link local address is distributed. If DNS= is empty, DNS
1609 servers are read from the [Network] section. If the [Network]
1610 section does not contain any DNS servers either, DNS servers from
1611 the uplink with the highest priority default route are used. When
1612 EmitDNS= is false, no DNS server information is sent in Router
1613 Advertisement messages. EmitDNS= defaults to true.
1614 EmitDomains=, Domains=
1616 A list of DNS search domains distributed via Router Advertisement
1617 messages when EmitDomains= is true. If Domains= is empty, DNS
1618 search domains are read from the [Network] section. If the
1619 [Network] section does not contain any DNS search domains either,
1620 DNS search domains from the uplink with the highest priority
1621 default route are used. When EmitDomains= is false, no DNS search
1622 domain information is sent in Router Advertisement messages.
1623 EmitDomains= defaults to true.
1624 DNSLifetimeSec=
1626 Lifetime in seconds for the DNS server addresses listed in DNS= and
1627 search domains listed in Domains=.
1628
1630 One or more [IPv6Prefix] sections contain the IPv6 prefixes that are
1631 announced via Router Advertisements. See RFC 4861[22] for further
1632 details.
1633 AddressAutoconfiguration=, OnLink=
1635 Takes a boolean to specify whether IPv6 addresses can be
1636 autoconfigured with this prefix and whether the prefix can be used
1637 for onlink determination. Both settings default to "true" in order
1638 to ease configuration.
1639 Prefix=
1641 The IPv6 prefix that is to be distributed to hosts. Similarly to
1642 configuring static IPv6 addresses, the setting is configured as an
1643 IPv6 prefix and its prefix length, separated by a "/" character.
1644 Use multiple [IPv6Prefix] sections to configure multiple IPv6
1645 prefixes since prefix lifetimes, address autoconfiguration and
1646 onlink status may differ from one prefix to another.
1647 PreferredLifetimeSec=, ValidLifetimeSec=
1649 Preferred and valid lifetimes for the prefix measured in seconds.
1650 PreferredLifetimeSec= defaults to 604800 seconds (one week) and
1651 ValidLifetimeSec= defaults to 2592000 seconds (30 days).
1652 Assign=
1654 Takes a boolean. When true, adds an address from the prefix.
1655 Default to false.
1656
1658 One or more [IPv6RoutePrefix] sections contain the IPv6 prefix routes
1659 that are announced via Router Advertisements. See RFC 4191[15] for
1660 further details.
1661 Route=
1663 The IPv6 route that is to be distributed to hosts. Similarly to
1664 configuring static IPv6 routes, the setting is configured as an
1665 IPv6 prefix routes and its prefix route length, separated by a "/"
1666 character. Use multiple [IPv6PrefixRoutes] sections to configure
1667 multiple IPv6 prefix routes.
1668 LifetimeSec=
1670 Lifetime for the route prefix measured in seconds. LifetimeSec=
1671 defaults to 604800 seconds (one week).
1672
1674 The [Bridge] section accepts the following keys:
1675 UnicastFlood=
1677 Takes a boolean. Controls whether the bridge should flood traffic
1678 for which an FDB entry is missing and the destination is unknown
1679 through this port. When unset, the kernel's default will be used.
1680 MulticastFlood=
1682 Takes a boolean. Controls whether the bridge should flood traffic
1683 for which an MDB entry is missing and the destination is unknown
1684 through this port. When unset, the kernel's default will be used.
1685 MulticastToUnicast=
1687 Takes a boolean. Multicast to unicast works on top of the multicast
1688 snooping feature of the bridge. Which means unicast copies are only
1689 delivered to hosts which are interested in it. When unset, the
1690 kernel's default will be used.
1691 NeighborSuppression=
1693 Takes a boolean. Configures whether ARP and ND neighbor suppression
1694 is enabled for this port. When unset, the kernel's default will be
1695 used.
1696 Learning=
1698 Takes a boolean. Configures whether MAC address learning is enabled
1699 for this port. When unset, the kernel's default will be used.
1700 HairPin=
1702 Takes a boolean. Configures whether traffic may be sent back out of
1703 the port on which it was received. When this flag is false, then
1704 the bridge will not forward traffic back out of the receiving port.
1705 When unset, the kernel's default will be used.
1706 UseBPDU=
1708 Takes a boolean. Configures whether STP Bridge Protocol Data Units
1709 will be processed by the bridge port. When unset, the kernel's
1710 default will be used.
1711 FastLeave=
1713 Takes a boolean. This flag allows the bridge to immediately stop
1714 multicast traffic on a port that receives an IGMP Leave message. It
1715 is only used with IGMP snooping if enabled on the bridge. When
1716 unset, the kernel's default will be used.
1717 AllowPortToBeRoot=
1719 Takes a boolean. Configures whether a given port is allowed to
1720 become a root port. Only used when STP is enabled on the bridge.
1721 When unset, the kernel's default will be used.
1722 ProxyARP=
1724 Takes a boolean. Configures whether proxy ARP to be enabled on this
1725 port. When unset, the kernel's default will be used.
1726 ProxyARPWiFi=
1728 Takes a boolean. Configures whether proxy ARP to be enabled on this
1729 port which meets extended requirements by IEEE 802.11 and Hotspot
1730 2.0 specifications. When unset, the kernel's default will be used.
1731 MulticastRouter=
1733 Configures this port for having multicast routers attached. A port
1734 with a multicast router will receive all multicast traffic. Takes
1735 one of "no" to disable multicast routers on this port, "query" to
1736 let the system detect the presence of routers, "permanent" to
1737 permanently enable multicast traffic forwarding on this port, or
1738 "temporary" to enable multicast routers temporarily on this port,
1739 not depending on incoming queries. When unset, the kernel's default
1740 will be used.
1741 Cost=
1743 Sets the "cost" of sending packets of this interface. Each port in
1744 a bridge may have a different speed and the cost is used to decide
1745 which link to use. Faster interfaces should have lower costs. It is
1746 an integer value between 1 and 65535.
1747 Priority=
1749 Sets the "priority" of sending packets on this interface. Each port
1750 in a bridge may have a different priority which is used to decide
1751 which link to use. Lower value means higher priority. It is an
1752 integer value between 0 to 63. Networkd does not set any default,
1753 meaning the kernel default value of 32 is used.
1754
1756 The [BridgeFDB] section manages the forwarding database table of a port
1757 and accepts the following keys. Specify several [BridgeFDB] sections to
1758 configure several static MAC table entries.
1759 MACAddress=
1761 As in the [Network] section. This key is mandatory.
1762 Destination=
1764 Takes an IP address of the destination VXLAN tunnel endpoint.
1765 VLANId=
1767 The VLAN ID for the new static MAC table entry. If omitted, no VLAN
1768 ID information is appended to the new static MAC table entry.
1769 VNI=
1771 The VXLAN Network Identifier (or VXLAN Segment ID) to use to
1772 connect to the remote VXLAN tunnel endpoint. Takes a number in the
1773 range 1-16777215. Defaults to unset.
1774 AssociatedWith=
1776 Specifies where the address is associated with. Takes one of "use",
1777 "self", "master" or "router". "use" means the address is in use.
1778 User space can use this option to indicate to the kernel that the
1779 fdb entry is in use. "self" means the address is associated with
1780 the port drivers fdb. Usually hardware. "master" means the address
1781 is associated with master devices fdb. "router" means the
1782 destination address is associated with a router. Note that it's
1783 valid if the referenced device is a VXLAN type device and has route
1784 shortcircuit enabled. Defaults to "self".
1785
1787 The [LLDP] section manages the Link Layer Discovery Protocol (LLDP) and
1788 accepts the following keys.
1789 MUDURL=
1791 Controls support for Ethernet LLDP packet's Manufacturer Usage
1792 Description (MUD). MUD is an embedded software standard defined by
1793 the IETF that allows IoT Device makers to advertise device
1794 specifications, including the intended communication patterns for
1795 their device when it connects to the network. The network can then
1796 use this intent to author a context-specific access policy, so the
1797 device functions only within those parameters. Takes an URL of
1798 length up to 255 characters. A superficial verification that the
1799 string is a valid URL will be performed. See RFC 8520[17] for
1800 details. The MUD URL received from the LLDP packets will be saved
1801 at the state files and can be read via
1802 sd_lldp_neighbor_get_mud_url() function.
1803
1805 The [CAN] section manages the Controller Area Network (CAN bus) and
1806 accepts the following keys:
1807 BitRate=
1809 The bitrate of CAN device in bits per second. The usual SI prefixes
1810 (K, M) with the base of 1000 can be used here. Takes a number in
1811 the range 1..4294967295.
1812 SamplePoint=
1814 Optional sample point in percent with one decimal (e.g. "75%",
1815 "87.5%") or permille (e.g. "875‰").
1816 DataBitRate=, DataSamplePoint=
1818 The bitrate and sample point for the data phase, if CAN-FD is used.
1819 These settings are analogous to the BitRate= and SamplePoint= keys.
1820 FDMode=
1822 Takes a boolean. When "yes", CAN-FD mode is enabled for the
1823 interface. Note, that a bitrate and optional sample point should
1824 also be set for the CAN-FD data phase using the DataBitRate= and
1825 DataSamplePoint= keys.
1826 FDNonISO=
1828 Takes a boolean. When "yes", non-ISO CAN-FD mode is enabled for the
1829 interface. When unset, the kernel's default will be used.
1830 RestartSec=
1832 Automatic restart delay time. If set to a non-zero value, a restart
1833 of the CAN controller will be triggered automatically in case of a
1834 bus-off condition after the specified delay time. Subsecond delays
1835 can be specified using decimals (e.g. "0.1s") or a "ms" or "us"
1836 postfix. Using "infinity" or "0" will turn the automatic restart
1837 off. By default automatic restart is disabled.
1838 Termination=
1840 Takes a boolean. When "yes", the termination resistor will be
1841 selected for the bias network. When unset, the kernel's default
1842 will be used.
1843 TripleSampling=
1845 Takes a boolean. When "yes", three samples (instead of one) are
1846 used to determine the value of a received bit by majority rule.
1847 When unset, the kernel's default will be used.
1848 ListenOnly=
1850 Takes a boolean. When "yes", listen-only mode is enabled. When the
1851 interface is in listen-only mode, the interface neither transmit
1852 CAN frames nor send ACK bit. Listen-only mode is important to debug
1853 CAN networks without interfering with the communication or
1854 acknowledge the CAN frame. When unset, the kernel's default will be
1855 used.
1856
1858 The [QDisc] section manages the traffic control queueing discipline
1859 (qdisc).
1860 Parent=
1862 Specifies the parent Queueing Discipline (qdisc). Takes one of
1863 "clsact" or "ingress". This is mandatory.
1864 Handle=
1866 Configures the major number of unique identifier of the qdisc,
1867 known as the handle. Takes a hexadecimal number in the range
1868 0x1–0xffff. Defaults to unset.
1869
1871 The [NetworkEmulator] section manages the queueing discipline (qdisc)
1872 of the network emulator. It can be used to configure the kernel packet
1873 scheduler and simulate packet delay and loss for UDP or TCP
1874 applications, or limit the bandwidth usage of a particular service to
1875 simulate internet connections.
1876 Parent=
1878 Configures the parent Queueing Discipline (qdisc). Takes one of
1879 "root", "clsact", "ingress" or a class identifier. The class
1880 identifier is specified as the major and minor numbers in
1881 hexadecimal in the range 0x1–Oxffff separated with a colon
1882 ("major:minor"). Defaults to "root".
1883 Handle=
1885 Configures the major number of unique identifier of the qdisc,
1886 known as the handle. Takes a hexadecimal number in the range
1887 0x1–0xffff. Defaults to unset.
1888 DelaySec=
1890 Specifies the fixed amount of delay to be added to all packets
1891 going out of the interface. Defaults to unset.
1892 DelayJitterSec=
1894 Specifies the chosen delay to be added to the packets outgoing to
1895 the network interface. Defaults to unset.
1896 PacketLimit=
1898 Specifies the maximum number of packets the qdisc may hold queued
1899 at a time. An unsigned integer in the range 0–4294967294. Defaults
1900 to 1000.
1901 LossRate=
1903 Specifies an independent loss probability to be added to the
1904 packets outgoing from the network interface. Takes a percentage
1905 value, suffixed with "%". Defaults to unset.
1906 DuplicateRate=
1908 Specifies that the chosen percent of packets is duplicated before
1909 queuing them. Takes a percentage value, suffixed with "%". Defaults
1910 to unset.
1911
1913 The [TokenBucketFilter] section manages the queueing discipline (qdisc)
1914 of token bucket filter (tbf).
1915 Parent=
1917 Configures the parent Queueing Discipline (qdisc). Takes one of
1918 "root", "clsact", "ingress" or a class identifier. The class
1919 identifier is specified as the major and minor numbers in
1920 hexadecimal in the range 0x1–Oxffff separated with a colon
1921 ("major:minor"). Defaults to "root".
1922 Handle=
1924 Configures the major number of unique identifier of the qdisc,
1925 known as the handle. Takes a hexadecimal number in the range
1926 0x1–0xffff. Defaults to unset.
1927 LatencySec=
1929 Specifies the latency parameter, which specifies the maximum amount
1930 of time a packet can sit in the Token Bucket Filter (TBF). Defaults
1931 to unset.
1932 LimitBytes=
1934 Takes the number of bytes that can be queued waiting for tokens to
1935 become available. When the size is suffixed with K, M, or G, it is
1936 parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the
1937 base of 1024. Defaults to unset.
1938 BurstBytes=
1940 Specifies the size of the bucket. This is the maximum amount of
1941 bytes that tokens can be available for instantaneous transfer. When
1942 the size is suffixed with K, M, or G, it is parsed as Kilobytes,
1943 Megabytes, or Gigabytes, respectively, to the base of 1024.
1944 Defaults to unset.
1945 Rate=
1947 Specifies the device specific bandwidth. When suffixed with K, M,
1948 or G, the specified bandwidth is parsed as Kilobits, Megabits, or
1949 Gigabits, respectively, to the base of 1000. Defaults to unset.
1950 MPUBytes=
1952 The Minimum Packet Unit (MPU) determines the minimal token usage
1953 (specified in bytes) for a packet. When suffixed with K, M, or G,
1954 the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
1955 respectively, to the base of 1024. Defaults to zero.
1956 PeakRate=
1958 Takes the maximum depletion rate of the bucket. When suffixed with
1959 K, M, or G, the specified size is parsed as Kilobits, Megabits, or
1960 Gigabits, respectively, to the base of 1000. Defaults to unset.
1961 MTUBytes=
1963 Specifies the size of the peakrate bucket. When suffixed with K, M,
1964 or G, the specified size is parsed as Kilobytes, Megabytes, or
1965 Gigabytes, respectively, to the base of 1024. Defaults to unset.
1966
1968 The [PIE] section manages the queueing discipline (qdisc) of
1969 Proportional Integral controller-Enhanced (PIE).
1970 Parent=
1972 Configures the parent Queueing Discipline (qdisc). Takes one of
1973 "root", "clsact", "ingress" or a class identifier. The class
1974 identifier is specified as the major and minor numbers in
1975 hexadecimal in the range 0x1–Oxffff separated with a colon
1976 ("major:minor"). Defaults to "root".
1977 Handle=
1979 Configures the major number of unique identifier of the qdisc,
1980 known as the handle. Takes a hexadecimal number in the range
1981 0x1–0xffff. Defaults to unset.
1982 PacketLimit=
1984 Specifies the hard limit on the queue size in number of packets.
1985 When this limit is reached, incoming packets are dropped. An
1986 unsigned integer in the range 1–4294967294. Defaults to unset and
1987 kernel's default is used.
1988
1990 The [StochasticFairBlue] section manages the queueing discipline
1991 (qdisc) of stochastic fair blue (sfb).
1992 Parent=
1994 Configures the parent Queueing Discipline (qdisc). Takes one of
1995 "root", "clsact", "ingress" or a class identifier. The class
1996 identifier is specified as the major and minor numbers in
1997 hexadecimal in the range 0x1–Oxffff separated with a colon
1998 ("major:minor"). Defaults to "root".
1999 Handle=
2001 Configures the major number of unique identifier of the qdisc,
2002 known as the handle. Takes a hexadecimal number in the range
2003 0x1–0xffff. Defaults to unset.
2004 PacketLimit=
2006 Specifies the hard limit on the queue size in number of packets.
2007 When this limit is reached, incoming packets are dropped. An
2008 unsigned integer in the range 0–4294967294. Defaults to unset and
2009 kernel's default is used.
2010
2012 The [StochasticFairnessQueueing] section manages the queueing
2013 discipline (qdisc) of stochastic fairness queueing (sfq).
2014 Parent=
2016 Configures the parent Queueing Discipline (qdisc). Takes one of
2017 "root", "clsact", "ingress" or a class identifier. The class
2018 identifier is specified as the major and minor numbers in
2019 hexadecimal in the range 0x1–Oxffff separated with a colon
2020 ("major:minor"). Defaults to "root".
2021 Handle=
2023 Configures the major number of unique identifier of the qdisc,
2024 known as the handle. Takes a hexadecimal number in the range
2025 0x1–0xffff. Defaults to unset.
2026 PerturbPeriodSec=
2028 Specifies the interval in seconds for queue algorithm perturbation.
2029 Defaults to unset.
2030
2032 The [BFIFO] section manages the queueing discipline (qdisc) of Byte
2033 limited Packet First In First Out (bfifo).
2034 Parent=
2036 Configures the parent Queueing Discipline (qdisc). Takes one of
2037 "root", "clsact", "ingress" or a class identifier. The class
2038 identifier is specified as the major and minor numbers in
2039 hexadecimal in the range 0x1–Oxffff separated with a colon
2040 ("major:minor"). Defaults to "root".
2041 Handle=
2043 Configures the major number of unique identifier of the qdisc,
2044 known as the handle. Takes a hexadecimal number in the range
2045 0x1–0xffff. Defaults to unset.
2046 LimitBytes=
2048 Specifies the hard limit on the FIFO size in bytes. The size limit
2049 (a buffer size) to prevent it from overflowing in case it is unable
2050 to dequeue packets as quickly as it receives them. When this limit
2051 is reached, incoming packets are dropped. When suffixed with K, M,
2052 or G, the specified size is parsed as Kilobytes, Megabytes, or
2053 Gigabytes, respectively, to the base of 1024. Defaults to unset and
2054 kernel's default is used.
2055
2057 The [PFIFO] section manages the queueing discipline (qdisc) of Packet
2058 First In First Out (pfifo).
2059 Parent=
2061 Configures the parent Queueing Discipline (qdisc). Takes one of
2062 "root", "clsact", "ingress" or a class identifier. The class
2063 identifier is specified as the major and minor numbers in
2064 hexadecimal in the range 0x1–Oxffff separated with a colon
2065 ("major:minor"). Defaults to "root".
2066 Handle=
2068 Configures the major number of unique identifier of the qdisc,
2069 known as the handle. Takes a hexadecimal number in the range
2070 0x1–0xffff. Defaults to unset.
2071 PacketLimit=
2073 Specifies the hard limit on the FIFO size in number of packets. The
2074 size limit (a buffer size) to prevent it from overflowing in case
2075 it is unable to dequeue packets as quickly as it receives them.
2076 When this limit is reached, incoming packets are dropped. An
2077 unsigned integer in the range 0–4294967294. Defaults to unset and
2078 kernel's default is used.
2079
2081 The [PFIFOHeadDrop] section manages the queueing discipline (qdisc) of
2082 Packet First In First Out Head Drop (pfifo_head_drop).
2083 Parent=
2085 Configures the parent Queueing Discipline (qdisc). Takes one of
2086 "root", "clsact", "ingress" or a class identifier. The class
2087 identifier is specified as the major and minor numbers in
2088 hexadecimal in the range 0x1–Oxffff separated with a colon
2089 ("major:minor"). Defaults to "root".
2090 Handle=
2092 Configures the major number of unique identifier of the qdisc,
2093 known as the handle. Takes a hexadecimal number in the range
2094 0x1–0xffff. Defaults to unset.
2095 PacketLimit=
2097 As in [PFIFO] section.
2098
2100 The [PFIFOFast] section manages the queueing discipline (qdisc) of
2101 Packet First In First Out Fast (pfifo_fast).
2102 Parent=
2104 Configures the parent Queueing Discipline (qdisc). Takes one of
2105 "root", "clsact", "ingress" or a class identifier. The class
2106 identifier is specified as the major and minor numbers in
2107 hexadecimal in the range 0x1–Oxffff separated with a colon
2108 ("major:minor"). Defaults to "root".
2109 Handle=
2111 Configures the major number of unique identifier of the qdisc,
2112 known as the handle. Takes a hexadecimal number in the range
2113 0x1–0xffff. Defaults to unset.
2114
2116 The [CAKE] section manages the queueing discipline (qdisc) of Common
2117 Applications Kept Enhanced (CAKE).
2118 Parent=
2120 Configures the parent Queueing Discipline (qdisc). Takes one of
2121 "root", "clsact", "ingress" or a class identifier. The class
2122 identifier is specified as the major and minor numbers in
2123 hexadecimal in the range 0x1–Oxffff separated with a colon
2124 ("major:minor"). Defaults to "root".
2125 Handle=
2127 Configures the major number of unique identifier of the qdisc,
2128 known as the handle. Takes a hexadecimal number in the range
2129 0x1–0xffff. Defaults to unset.
2130 OverheadBytes=
2132 Specifies that bytes to be addeded to the size of each packet.
2133 Bytes may be negative. Takes an integer in the range from -64 to
2134 256. Defaults to unset and kernel's default is used.
2135 Bandwidth=
2137 Specifies the shaper bandwidth. When suffixed with K, M, or G, the
2138 specified size is parsed as Kilobits, Megabits, or Gigabits,
2139 respectively, to the base of 1000. Defaults to unset and kernel's
2140 default is used.
2141
2143 The [ControlledDelay] section manages the queueing discipline (qdisc)
2144 of controlled delay (CoDel).
2145 Parent=
2147 Configures the parent Queueing Discipline (qdisc). Takes one of
2148 "root", "clsact", "ingress" or a class identifier. The class
2149 identifier is specified as the major and minor numbers in
2150 hexadecimal in the range 0x1–Oxffff separated with a colon
2151 ("major:minor"). Defaults to "root".
2152 Handle=
2154 Configures the major number of unique identifier of the qdisc,
2155 known as the handle. Takes a hexadecimal number in the range
2156 0x1–0xffff. Defaults to unset.
2157 PacketLimit=
2159 Specifies the hard limit on the queue size in number of packets.
2160 When this limit is reached, incoming packets are dropped. An
2161 unsigned integer in the range 0–4294967294. Defaults to unset and
2162 kernel's default is used.
2163 TargetSec=
2165 Takes a timespan. Specifies the acceptable minimum
2166 standing/persistent queue delay. Defaults to unset and kernel's
2167 default is used.
2168 IntervalSec=
2170 Takes a timespan. This is used to ensure that the measured minimum
2171 delay does not become too stale. Defaults to unset and kernel's
2172 default is used.
2173 ECN=
2175 Takes a boolean. This can be used to mark packets instead of
2176 dropping them. Defaults to unset and kernel's default is used.
2177 CEThresholdSec=
2179 Takes a timespan. This sets a threshold above which all packets are
2180 marked with ECN Congestion Experienced (CE). Defaults to unset and
2181 kernel's default is used.
2182
2184 The [DeficitRoundRobinScheduler] section manages the queueing
2185 discipline (qdisc) of Deficit Round Robin Scheduler (DRR).
2186 Parent=
2188 Configures the parent Queueing Discipline (qdisc). Takes one of
2189 "root", "clsact", "ingress" or a class identifier. The class
2190 identifier is specified as the major and minor numbers in
2191 hexadecimal in the range 0x1–Oxffff separated with a colon
2192 ("major:minor"). Defaults to "root".
2193 Handle=
2195 Configures the major number of unique identifier of the qdisc,
2196 known as the handle. Takes a hexadecimal number in the range
2197 0x1–0xffff. Defaults to unset.
2198
2200 The [DeficitRoundRobinSchedulerClass] section manages the traffic
2201 control class of Deficit Round Robin Scheduler (DRR).
2202 Parent=
2204 Configures the parent Queueing Discipline (qdisc). Takes one of
2205 "root", or a qdisc identifier. The qdisc identifier is specified as
2206 the major and minor numbers in hexadecimal in the range 0x1–Oxffff
2207 separated with a colon ("major:minor"). Defaults to "root".
2208 ClassId=
2210 Configues the unique identifier of the class. It is specified as
2211 the major and minor numbers in hexadecimal in the range 0x1–Oxffff
2212 separated with a colon ("major:minor"). Defaults to unset.
2213 QuantumBytes=
2215 Specifies the amount of bytes a flow is allowed to dequeue before
2216 the scheduler moves to the next class. When suffixed with K, M, or
2217 G, the specified size is parsed as Kilobytes, Megabytes, or
2218 Gigabytes, respectively, to the base of 1024. Defaults to the MTU
2219 of the interface.
2220
2222 The [EnhancedTransmissionSelection] section manages the queueing
2223 discipline (qdisc) of Enhanced Transmission Selection (ETS).
2224 Parent=
2226 Configures the parent Queueing Discipline (qdisc). Takes one of
2227 "root", "clsact", "ingress" or a class identifier. The class
2228 identifier is specified as the major and minor numbers in
2229 hexadecimal in the range 0x1–Oxffff separated with a colon
2230 ("major:minor"). Defaults to "root".
2231 Handle=
2233 Configures the major number of unique identifier of the qdisc,
2234 known as the handle. Takes a hexadecimal number in the range
2235 0x1–0xffff. Defaults to unset.
2236 Bands=
2238 Specifies the number of bands. An unsigned integer in the range
2239 1–16. This value has to be at least large enough to cover the
2240 strict bands specified through the StrictBands= and
2241 bandwidth-sharing bands specified in QuantumBytes=.
2242 StrictBands=
2244 Specifies the number of bands that should be created in strict
2245 mode. An unsigned integer in the range 1–16.
2246 QuantumBytes=
2248 Specifies the white-space separated list of quantum used in
2249 band-sharing bands. When suffixed with K, M, or G, the specified
2250 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively,
2251 to the base of 1024. This setting can be specified multiple times.
2252 If an empty string is assigned, then the all previous assignments
2253 are cleared.
2254 PriorityMap=
2256 The priority map maps the priority of a packet to a band. The
2257 argument is a white-space separated list of numbers. The first
2258 number indicates which band the packets with priority 0 should be
2259 put to, the second is for priority 1, and so on. There can be up to
2260 16 numbers in the list. If there are fewer, the default band that
2261 traffic with one of the unmentioned priorities goes to is the last
2262 one. Each band number must be 0..255. This setting can be specified
2263 multiple times. If an empty string is assigned, then the all
2264 previous assignments are cleared.
2265
2267 The [GenericRandomEarlyDetection] section manages the queueing
2268 discipline (qdisc) of Generic Random Early Detection (GRED).
2269 Parent=
2271 Configures the parent Queueing Discipline (qdisc). Takes one of
2272 "root", "clsact", "ingress" or a class identifier. The class
2273 identifier is specified as the major and minor numbers in
2274 hexadecimal in the range 0x1–Oxffff separated with a colon
2275 ("major:minor"). Defaults to "root".
2276 Handle=
2278 Configures the major number of unique identifier of the qdisc,
2279 known as the handle. Takes a hexadecimal number in the range
2280 0x1–0xffff. Defaults to unset.
2281 VirtualQueues=
2283 Specifies the number of virtual queues. Takes a integer in the
2284 range 1-16. Defaults to unset and kernel's default is used.
2285 DefaultVirtualQueue=
2287 Specifies the number of default virtual queue. This must be less
2288 than VirtualQueue=. Defaults to unset and kernel's default is used.
2289 GenericRIO=
2291 Takes a boolean. It turns on the RIO-like buffering scheme.
2292 Defaults to unset and kernel's default is used.
2293
2295 The [FairQueueingControlledDelay] section manages the queueing
2296 discipline (qdisc) of fair queuing controlled delay (FQ-CoDel).
2297 Parent=
2299 Configures the parent Queueing Discipline (qdisc). Takes one of
2300 "root", "clsact", "ingress" or a class identifier. The class
2301 identifier is specified as the major and minor numbers in
2302 hexadecimal in the range 0x1–Oxffff separated with a colon
2303 ("major:minor"). Defaults to "root".
2304 Handle=
2306 Configures the major number of unique identifier of the qdisc,
2307 known as the handle. Takes a hexadecimal number in the range
2308 0x1–0xffff. Defaults to unset.
2309 PacketLimit=
2311 Specifies the hard limit on the real queue size. When this limit is
2312 reached, incoming packets are dropped. Defaults to unset and
2313 kernel's default is used.
2314 MemoryLimitBytes=
2316 Specifies the limit on the total number of bytes that can be queued
2317 in this FQ-CoDel instance. When suffixed with K, M, or G, the
2318 specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
2319 respectively, to the base of 1024. Defaults to unset and kernel's
2320 default is used.
2321 Flows=
2323 Specifies the number of flows into which the incoming packets are
2324 classified. Defaults to unset and kernel's default is used.
2325 TargetSec=
2327 Takes a timespan. Specifies the acceptable minimum
2328 standing/persistent queue delay. Defaults to unset and kernel's
2329 default is used.
2330 IntervalSec=
2332 Takes a timespan. This is used to ensure that the measured minimum
2333 delay does not become too stale. Defaults to unset and kernel's
2334 default is used.
2335 QuantumBytes=
2337 Specifies the number of bytes used as the "deficit" in the fair
2338 queuing algorithm timespan. When suffixed with K, M, or G, the
2339 specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
2340 respectively, to the base of 1024. Defaults to unset and kernel's
2341 default is used.
2342 ECN=
2344 Takes a boolean. This can be used to mark packets instead of
2345 dropping them. Defaults to unset and kernel's default is used.
2346 CEThresholdSec=
2348 Takes a timespan. This sets a threshold above which all packets are
2349 marked with ECN Congestion Experienced (CE). Defaults to unset and
2350 kernel's default is used.
2351
2353 The [FairQueueing] section manages the queueing discipline (qdisc) of
2354 fair queue traffic policing (FQ).
2355 Parent=
2357 Configures the parent Queueing Discipline (qdisc). Takes one of
2358 "root", "clsact", "ingress" or a class identifier. The class
2359 identifier is specified as the major and minor numbers in
2360 hexadecimal in the range 0x1–Oxffff separated with a colon
2361 ("major:minor"). Defaults to "root".
2362 Handle=
2364 Configures the major number of unique identifier of the qdisc,
2365 known as the handle. Takes a hexadecimal number in the range
2366 0x1–0xffff. Defaults to unset.
2367 PacketLimit=
2369 Specifies the hard limit on the real queue size. When this limit is
2370 reached, incoming packets are dropped. Defaults to unset and
2371 kernel's default is used.
2372 FlowLimit=
2374 Specifies the hard limit on the maximum number of packets queued
2375 per flow. Defaults to unset and kernel's default is used.
2376 QuantumBytes=
2378 Specifies the credit per dequeue RR round, i.e. the amount of bytes
2379 a flow is allowed to dequeue at once. When suffixed with K, M, or
2380 G, the specified size is parsed as Kilobytes, Megabytes, or
2381 Gigabytes, respectively, to the base of 1024. Defaults to unset and
2382 kernel's default is used.
2383 InitialQuantumBytes=
2385 Specifies the initial sending rate credit, i.e. the amount of bytes
2386 a new flow is allowed to dequeue initially. When suffixed with K,
2387 M, or G, the specified size is parsed as Kilobytes, Megabytes, or
2388 Gigabytes, respectively, to the base of 1024. Defaults to unset and
2389 kernel's default is used.
2390 MaximumRate=
2392 Specifies the maximum sending rate of a flow. When suffixed with K,
2393 M, or G, the specified size is parsed as Kilobits, Megabits, or
2394 Gigabits, respectively, to the base of 1000. Defaults to unset and
2395 kernel's default is used.
2396 Buckets=
2398 Specifies the size of the hash table used for flow lookups.
2399 Defaults to unset and kernel's default is used.
2400 OrphanMask=
2402 Takes an unsigned integer. For packets not owned by a socket, fq is
2403 able to mask a part of hash and reduce number of buckets associated
2404 with the traffic. Defaults to unset and kernel's default is used.
2405 Pacing=
2407 Takes a boolean, and enables or disables flow pacing. Defaults to
2408 unset and kernel's default is used.
2409 CEThresholdSec=
2411 Takes a timespan. This sets a threshold above which all packets are
2412 marked with ECN Congestion Experienced (CE). Defaults to unset and
2413 kernel's default is used.
2414
2416 The [TrivialLinkEqualizer] section manages the queueing discipline
2417 (qdisc) of trivial link equalizer (teql).
2418 Parent=
2420 Configures the parent Queueing Discipline (qdisc). Takes one of
2421 "root", "clsact", "ingress" or a class identifier. The class
2422 identifier is specified as the major and minor numbers in
2423 hexadecimal in the range 0x1–Oxffff separated with a colon
2424 ("major:minor"). Defaults to "root".
2425 Handle=
2427 Configures the major number of unique identifier of the qdisc,
2428 known as the handle. Takes a hexadecimal number in the range
2429 0x1–0xffff. Defaults to unset.
2430 Id=
2432 Specifies the interface ID "N" of teql. Defaults to "0". Note that
2433 when teql is used, currently, the module sch_teql with
2434 max_equalizers=N+1 option must be loaded before systemd-networkd is
2435 started.
2436
2438 The [HierarchyTokenBucket] section manages the queueing discipline
2439 (qdisc) of hierarchy token bucket (htb).
2440 Parent=
2442 Configures the parent Queueing Discipline (qdisc). Takes one of
2443 "root", "clsact", "ingress" or a class identifier. The class
2444 identifier is specified as the major and minor numbers in
2445 hexadecimal in the range 0x1–Oxffff separated with a colon
2446 ("major:minor"). Defaults to "root".
2447 Handle=
2449 Configures the major number of unique identifier of the qdisc,
2450 known as the handle. Takes a hexadecimal number in the range
2451 0x1–0xffff. Defaults to unset.
2452 DefaultClass=
2454 Takes the minor id in hexadecimal of the default class.
2455 Unclassified traffic gets sent to the class. Defaults to unset.
2456 RateToQuantum=
2458 Takes an unsigned integer. The DRR quantums are calculated by
2459 dividing the value configured in Rate= by RateToQuantum=.
2460
2462 The [HierarchyTokenBucketClass] section manages the traffic control
2463 class of hierarchy token bucket (htb).
2464 Parent=
2466 Configures the parent Queueing Discipline (qdisc). Takes one of
2467 "root", or a qdisc identifier. The qdisc identifier is specified as
2468 the major and minor numbers in hexadecimal in the range 0x1–Oxffff
2469 separated with a colon ("major:minor"). Defaults to "root".
2470 ClassId=
2472 Configues the unique identifier of the class. It is specified as
2473 the major and minor numbers in hexadecimal in the range 0x1–Oxffff
2474 separated with a colon ("major:minor"). Defaults to unset.
2475 Priority=
2477 Specifies the priority of the class. In the round-robin process,
2478 classes with the lowest priority field are tried for packets first.
2479 QuantumBytes=
2481 Specifies how many bytes to serve from leaf at once. When suffixed
2482 with K, M, or G, the specified size is parsed as Kilobytes,
2483 Megabytes, or Gigabytes, respectively, to the base of 1024.
2484 MTUBytes=
2486 Specifies the maximum packet size we create. When suffixed with K,
2487 M, or G, the specified size is parsed as Kilobytes, Megabytes, or
2488 Gigabytes, respectively, to the base of 1024.
2489 OverheadBytes=
2491 Takes an unsigned integer which specifies per-packet size overhead
2492 used in rate computations. When suffixed with K, M, or G, the
2493 specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
2494 respectively, to the base of 1024.
2495 Rate=
2497 Specifies the maximum rate this class and all its children are
2498 guaranteed. When suffixed with K, M, or G, the specified size is
2499 parsed as Kilobits, Megabits, or Gigabits, respectively, to the
2500 base of 1000. This setting is mandatory.
2501 CeilRate=
2503 Specifies the maximum rate at which a class can send, if its parent
2504 has bandwidth to spare. When suffixed with K, M, or G, the
2505 specified size is parsed as Kilobits, Megabits, or Gigabits,
2506 respectively, to the base of 1000. When unset, the value specified
2507 with Rate= is used.
2508 BufferBytes=
2510 Specifies the maximum bytes burst which can be accumulated during
2511 idle period. When suffixed with K, M, or G, the specified size is
2512 parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the
2513 base of 1024.
2514 CeilBufferBytes=
2516 Specifies the maximum bytes burst for ceil which can be accumulated
2517 during idle period. When suffixed with K, M, or G, the specified
2518 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively,
2519 to the base of 1024.
2520
2522 The [HeavyHitterFilter] section manages the queueing discipline (qdisc)
2523 of Heavy Hitter Filter (hhf).
2524 Parent=
2526 Configures the parent Queueing Discipline (qdisc). Takes one of
2527 "root", "clsact", "ingress" or a class identifier. The class
2528 identifier is specified as the major and minor numbers in
2529 hexadecimal in the range 0x1–Oxffff separated with a colon
2530 ("major:minor"). Defaults to "root".
2531 Handle=
2533 Configures the major number of unique identifier of the qdisc,
2534 known as the handle. Takes a hexadecimal number in the range
2535 0x1–0xffff. Defaults to unset.
2536 PacketLimit=
2538 Specifies the hard limit on the queue size in number of packets.
2539 When this limit is reached, incoming packets are dropped. An
2540 unsigned integer in the range 0–4294967294. Defaults to unset and
2541 kernel's default is used.
2542
2544 The [QuickFairQueueing] section manages the queueing discipline (qdisc)
2545 of Quick Fair Queueing (QFQ).
2546 Parent=
2548 Configures the parent Queueing Discipline (qdisc). Takes one of
2549 "root", "clsact", "ingress" or a class identifier. The class
2550 identifier is specified as the major and minor numbers in
2551 hexadecimal in the range 0x1–Oxffff separated with a colon
2552 ("major:minor"). Defaults to "root".
2553 Handle=
2555 Configures the major number of unique identifier of the qdisc,
2556 known as the handle. Takes a hexadecimal number in the range
2557 0x1–0xffff. Defaults to unset.
2558
2560 The [QuickFairQueueingClass] section manages the traffic control class
2561 of Quick Fair Queueing (qfq).
2562 Parent=
2564 Configures the parent Queueing Discipline (qdisc). Takes one of
2565 "root", or a qdisc identifier. The qdisc identifier is specified as
2566 the major and minor numbers in hexadecimal in the range 0x1–Oxffff
2567 separated with a colon ("major:minor"). Defaults to "root".
2568 ClassId=
2570 Configues the unique identifier of the class. It is specified as
2571 the major and minor numbers in hexadecimal in the range 0x1–Oxffff
2572 separated with a colon ("major:minor"). Defaults to unset.
2573 Weight=
2575 Specifies the weight of the class. Takes an integer in the range
2576 1..1023. Defaults to unset in which case the kernel default is
2577 used.
2578 MaxPacketBytes=
2580 Specifies the maximum packet size in bytes for the class. When
2581 suffixed with K, M, or G, the specified size is parsed as
2582 Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
2583 1024. When unset, the kernel default is used.
2584
2586 The [BridgeVLAN] section manages the VLAN ID configuration of a bridge
2587 port and accepts the following keys. Specify several [BridgeVLAN]
2588 sections to configure several VLAN entries. The VLANFiltering= option
2589 has to be enabled, see the [Bridge] section in systemd.netdev(5).
2590 VLAN=
2592 The VLAN ID allowed on the port. This can be either a single ID or
2593 a range M-N. VLAN IDs are valid from 1 to 4094.
2594 EgressUntagged=
2596 The VLAN ID specified here will be used to untag frames on egress.
2597 Configuring EgressUntagged= implicates the use of VLAN= above and
2598 will enable the VLAN ID for ingress as well. This can be either a
2599 single ID or a range M-N.
2600 PVID=
2602 The Port VLAN ID specified here is assigned to all untagged frames
2603 at ingress. PVID= can be used only once. Configuring PVID=
2604 implicates the use of VLAN= above and will enable the VLAN ID for
2605 ingress as well.
2606
2608 Example 1. Static network configuration
2609 # /etc/systemd/network/50-static.network
2611 [Match]
2612 Name=enp2s0
2613 [Network]
2615 Address=192.168.0.15/24
2616 Gateway=192.168.0.1
2617 This brings interface "enp2s0" up with a static address. The specified
2619 gateway will be used for a default route.
2620 Example 2. DHCP on ethernet links
2622 # /etc/systemd/network/80-dhcp.network
2624 [Match]
2625 Name=en*
2626 [Network]
2628 DHCP=yes
2629 This will enable DHCPv4 and DHCPv6 on all interfaces with names
2631 starting with "en" (i.e. ethernet interfaces).
2632 Example 3. IPv6 Prefix Delegation
2634 # /etc/systemd/network/55-ipv6-pd-upstream.network
2636 [Match]
2637 Name=enp1s0
2638 [Network]
2640 DHCP=ipv6
2641 # /etc/systemd/network/56-ipv6-pd-downstream.network
2643 [Match]
2644 Name=enp2s0
2645 [Network]
2647 IPv6PrefixDelegation=dhcpv6
2648 This will enable IPv6 PD on the interface enp1s0 as an upstream
2650 interface where the DHCPv6 client is running and enp2s0 as a downstream
2651 interface where the prefix is delegated to.
2652 Example 4. A bridge with two enslaved links
2654 # /etc/systemd/network/25-bridge-static.network
2656 [Match]
2657 Name=bridge0
2658 [Network]
2660 Address=192.168.0.15/24
2661 Gateway=192.168.0.1
2662 DNS=192.168.0.1
2663 # /etc/systemd/network/25-bridge-slave-interface-1.network
2665 [Match]
2666 Name=enp2s0
2667 [Network]
2669 Bridge=bridge0
2670 # /etc/systemd/network/25-bridge-slave-interface-2.network
2672 [Match]
2673 Name=wlp3s0
2674 [Network]
2676 Bridge=bridge0
2677 This creates a bridge and attaches devices "enp2s0" and "wlp3s0" to it.
2679 The bridge will have the specified static address and network assigned,
2680 and a default route via the specified gateway will be added. The
2681 specified DNS server will be added to the global list of DNS resolvers.
2682 Example 5.
2684 # /etc/systemd/network/20-bridge-slave-interface-vlan.network
2686 [Match]
2687 Name=enp2s0
2688 [Network]
2690 Bridge=bridge0
2691 [BridgeVLAN]
2693 VLAN=1-32
2694 PVID=42
2695 EgressUntagged=42
2696 [BridgeVLAN]
2698 VLAN=100-200
2699 [BridgeVLAN]
2701 EgressUntagged=300-400
2702 This overrides the configuration specified in the previous example for
2704 the interface "enp2s0", and enables VLAN on that bridge port. VLAN IDs
2705 1-32, 42, 100-400 will be allowed. Packets tagged with VLAN IDs 42,
2706 300-400 will be untagged when they leave on this interface. Untagged
2707 packets which arrive on this interface will be assigned VLAN ID 42.
2708 Example 6. Various tunnels
2710 /etc/systemd/network/25-tunnels.network
2712 [Match]
2713 Name=ens1
2714 [Network]
2716 Tunnel=ipip-tun
2717 Tunnel=sit-tun
2718 Tunnel=gre-tun
2719 Tunnel=vti-tun
2720 /etc/systemd/network/25-tunnel-ipip.netdev
2723 [NetDev]
2724 Name=ipip-tun
2725 Kind=ipip
2726 /etc/systemd/network/25-tunnel-sit.netdev
2729 [NetDev]
2730 Name=sit-tun
2731 Kind=sit
2732 /etc/systemd/network/25-tunnel-gre.netdev
2735 [NetDev]
2736 Name=gre-tun
2737 Kind=gre
2738 /etc/systemd/network/25-tunnel-vti.netdev
2741 [NetDev]
2742 Name=vti-tun
2743 Kind=vti
2744 This will bring interface "ens1" up and create an IPIP tunnel, a SIT
2747 tunnel, a GRE tunnel, and a VTI tunnel using it.
2748 Example 7. A bond device
2750 # /etc/systemd/network/30-bond1.network
2752 [Match]
2753 Name=bond1
2754 [Network]
2756 DHCP=ipv6
2757 # /etc/systemd/network/30-bond1.netdev
2759 [NetDev]
2760 Name=bond1
2761 Kind=bond
2762 # /etc/systemd/network/30-bond1-dev1.network
2764 [Match]
2765 MACAddress=52:54:00:e9:64:41
2766 [Network]
2768 Bond=bond1
2769 # /etc/systemd/network/30-bond1-dev2.network
2771 [Match]
2772 MACAddress=52:54:00:e9:64:42
2773 [Network]
2775 Bond=bond1
2776 This will create a bond device "bond1" and enslave the two devices with
2778 MAC addresses 52:54:00:e9:64:41 and 52:54:00:e9:64:42 to it. IPv6 DHCP
2779 will be used to acquire an address.
2780 Example 8. Virtual Routing and Forwarding (VRF)
2782 Add the "bond1" interface to the VRF master interface "vrf1". This will
2784 redirect routes generated on this interface to be within the routing
2785 table defined during VRF creation. For kernels before 4.8 traffic won't
2786 be redirected towards the VRFs routing table unless specific ip-rules
2787 are added.
2788 # /etc/systemd/network/25-vrf.network
2790 [Match]
2791 Name=bond1
2792 [Network]
2794 VRF=vrf1
2795 Example 9. MacVTap
2797 This brings up a network interface "macvtap-test" and attaches it to
2799 "enp0s25".
2800 # /usr/lib/systemd/network/25-macvtap.network
2802 [Match]
2803 Name=enp0s25
2804 [Network]
2806 MACVTAP=macvtap-test
2807 Example 10. A Xfrm interface with physical underlying device.
2809 # /etc/systemd/network/27-xfrm.netdev
2811 [NetDev]
2812 Name=xfrm0
2813 [Xfrm]
2815 InterfaceId=7
2816 # /etc/systemd/network/27-eth0.network
2818 [Match]
2819 Name=eth0
2820 [Network]
2822 Xfrm=xfrm0
2823 This creates a "xfrm0" interface and binds it to the "eth0" device.
2825 This allows hardware based ipsec offloading to the "eth0" nic. If
2826 offloading is not needed, xfrm interfaces can be assigned to the "lo"
2827 device.
2828
2830 systemd(1), systemd-networkd.service(8), systemd.link(5),
2831 systemd.netdev(5), systemd-resolved.service(8)
2832
2834 1. RFC 7217
2835 https://tools.ietf.org/html/rfc7217
2836 2. Link-Local Multicast Name Resolution
2838 https://tools.ietf.org/html/rfc4795
2839 3. Multicast DNS
2841 https://tools.ietf.org/html/rfc6762
2842 4. DNS-over-TLS
2844 https://tools.ietf.org/html/rfc7858
2845 5. DNSSEC
2847 https://tools.ietf.org/html/rfc4033
2848 6. IEEE 802.1AB-2016
2850 https://standards.ieee.org/findstds/standard/802.1AB-2016.html
2851 7. ip-sysctl.txt
2853 https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt
2854 8. RFC 4941
2856 https://tools.ietf.org/html/rfc4941
2857 9. RFC 1027
2859 https://tools.ietf.org/html/rfc1027
2860 10. RFC 6275
2862 https://tools.ietf.org/html/rfc6275
2863 11. RFC 5224
2865 https://tools.ietf.org/html/rfc5227
2866 12. RFC 4862
2868 https://tools.ietf.org/html/rfc4862
2869 13. RFC 3041
2871 https://tools.ietf.org/html/rfc3041
2872 14. RFC 3484
2874 https://tools.ietf.org/html/rfc3484
2875 15. RFC 4191
2877 https://tools.ietf.org/html/rfc4191
2878 16. RFC 7844
2880 https://tools.ietf.org/html/rfc7844
2881 17. RFC 8520
2883 https://tools.ietf.org/html/rfc8520
2884 18. C-style escapes
2886 https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences
2887 19. RFC 3315
2889 https://tools.ietf.org/html/rfc3315#section-17.2.1
2890 20. RFC 7084
2892 https://tools.ietf.org/html/rfc7084
2893 21. RFC 4291
2895 https://tools.ietf.org/html/rfc4291#section-2.5.4
2896 22. RFC 4861
2898 https://tools.ietf.org/html/rfc4861
2899systemd 246 SYSTEMD.NETWORK(5)