1<?xml version='1.0'?> 2<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" 3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> 4<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> 5 6<refentry id="systemd-resolved.service" conditional='ENABLE_RESOLVE'> 7 8 <refentryinfo> 9 <title>systemd-resolved.service</title> 10 <productname>systemd</productname> 11 </refentryinfo> 12 13 <refmeta> 14 <refentrytitle>systemd-resolved.service</refentrytitle> 15 <manvolnum>8</manvolnum> 16 </refmeta> 17 18 <refnamediv> 19 <refname>systemd-resolved.service</refname> 20 <refname>systemd-resolved</refname> 21 <refpurpose>Network Name Resolution manager</refpurpose> 22 </refnamediv> 23 24 <refsynopsisdiv> 25 <para><filename>systemd-resolved.service</filename></para> 26 <para><filename>/usr/lib/systemd/systemd-resolved</filename></para> 27 </refsynopsisdiv> 28 29 <refsect1> 30 <title>Description</title> 31 32 <para><command>systemd-resolved</command> is a system service that provides network name resolution to 33 local applications. It implements a caching and validating DNS/DNSSEC stub resolver, as well as an LLMNR 34 and MulticastDNS resolver and responder. Local applications may submit network name resolution requests 35 via three interfaces:</para> 36 37 <itemizedlist> 38 <listitem><para>The native, fully-featured API <command>systemd-resolved</command> exposes on the bus, 39 see 40 <citerefentry><refentrytitle>org.freedesktop.resolve1</refentrytitle><manvolnum>5</manvolnum></citerefentry> 41 and 42 <citerefentry><refentrytitle>org.freedesktop.LogControl1</refentrytitle><manvolnum>5</manvolnum></citerefentry> 43 for details. Usage of this API is generally recommended to clients as it is asynchronous and fully 44 featured (for example, properly returns DNSSEC validation status and interface scope for addresses as 45 necessary for supporting link-local networking).</para></listitem> 46 47 <listitem><para>The glibc 48 <citerefentry project='man-pages'><refentrytitle>getaddrinfo</refentrytitle><manvolnum>3</manvolnum></citerefentry> 49 API as defined by <ulink url="https://tools.ietf.org/html/rfc3493">RFC3493</ulink> and its related 50 resolver functions, including 51 <citerefentry project='man-pages'><refentrytitle>gethostbyname</refentrytitle><manvolnum>3</manvolnum></citerefentry>. 52 This API is widely supported, including beyond the Linux platform. In its current form it does not 53 expose DNSSEC validation status information however, and is synchronous only. This API is backed by the 54 glibc Name Service Switch 55 (<citerefentry project='man-pages'><refentrytitle>nss</refentrytitle><manvolnum>5</manvolnum></citerefentry>). 56 Usage of the glibc NSS module 57 <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry> is 58 required in order to allow glibc's NSS resolver functions to resolve hostnames via 59 <command>systemd-resolved</command>.</para></listitem> 60 61 <listitem><para>Additionally, <command>systemd-resolved</command> provides a local DNS stub listener on 62 the IP addresses 127.0.0.53 and 127.0.0.54 on the local loopback interface. Programs issuing DNS 63 requests directly, bypassing any local API may be directed to this stub, in order to connect them to 64 <command>systemd-resolved</command>. Note however that it is strongly recommended that local programs 65 use the glibc NSS or bus APIs instead (as described above), as various network resolution concepts 66 (such as link-local addressing, or LLMNR Unicode domains) cannot be mapped to the unicast DNS 67 protocol.</para> 68 69 <para id="proxy-stub">The DNS stub resolver on 127.0.0.53 provides the full feature set of the local 70 resolver, which includes offering LLMNR/MulticastDNS resolution. The DNS stub resolver on 127.0.0.54 71 provides a more limited resolver, that operates in "proxy" mode only, i.e. it will pass most DNS 72 messages relatively unmodified to the current upstream DNS servers and back, but not try to process the 73 messages locally, and hence does not validate DNSSEC, or offer up LLMNR/MulticastDNS. (It will 74 translate to DNS-over-TLS communication if needed however.)</para></listitem> 75 </itemizedlist> 76 77 <para>The DNS servers contacted are determined from the global settings in 78 <filename>/etc/systemd/resolved.conf</filename>, the per-link static settings in 79 <filename>/etc/systemd/network/*.network</filename> files (in case 80 <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> 81 is used), the per-link dynamic settings received over DHCP, information provided via 82 <citerefentry><refentrytitle>resolvectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, and any 83 DNS server information made available by other system services. See 84 <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> and 85 <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry> for 86 details about systemd's own configuration files for DNS servers. To improve compatibility, 87 <filename>/etc/resolv.conf</filename> is read in order to discover configured system DNS servers, but 88 only if it is not a symlink to <filename>/run/systemd/resolve/stub-resolv.conf</filename>, 89 <filename>/usr/lib/systemd/resolv.conf</filename> or 90 <filename>/run/systemd/resolve/resolv.conf</filename> (see below).</para> 91 92 </refsect1> 93 94 <refsect1> 95 <title>Synthetic Records</title> 96 97 <para><command>systemd-resolved</command> synthesizes DNS resource records (RRs) for the following 98 cases:</para> 99 100 <itemizedlist> 101 <listitem><para>The local, configured hostname is resolved to all locally configured IP addresses 102 ordered by their scope, or — if none are configured — the IPv4 address 127.0.0.2 (which is on the local 103 loopback interface) and the IPv6 address ::1 (which is the local host).</para></listitem> 104 105 <listitem><para>The hostnames <literal>localhost</literal> and <literal>localhost.localdomain</literal> 106 as well as any hostname ending in <literal>.localhost</literal> or 107 <literal>.localhost.localdomain</literal> are resolved to the IP addresses 127.0.0.1 and ::1. 108 </para></listitem> 109 110 <listitem><para>The hostname <literal>_gateway</literal> is resolved to all current default routing 111 gateway addresses, ordered by their metric. This assigns a stable hostname to the current gateway, 112 useful for referencing it independently of the current network configuration state.</para></listitem> 113 114 <listitem><para>The hostname <literal>_outbound</literal> is resolved to the local IPv4 and IPv6 115 addresses that are most likely used for communication with other hosts. This is determined by 116 requesting a routing decision to the configured default gateways from the kernel and then using the 117 local IP addresses selected by this decision. This hostname is only available if there is at least one 118 local default gateway configured. This assigns a stable hostname to the local outbound IP addresses, 119 useful for referencing them independently of the current network configuration state.</para></listitem> 120 121 <listitem><para>The mappings defined in <filename>/etc/hosts</filename> are resolved to their 122 configured addresses and back, but they will not affect lookups for non-address types (like MX). 123 Support for <filename>/etc/hosts</filename> may be disabled with <varname>ReadEtcHosts=no</varname>, 124 see <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. 125 </para></listitem> 126 </itemizedlist> 127 </refsect1> 128 129 <refsect1> 130 <title>Protocols and Routing</title> 131 132 <para>The lookup requests that <filename>systemd-resolved.service</filename> receives are routed to the 133 available DNS servers, LLMNR, and MulticastDNS interfaces according to the following rules:</para> 134 135 <itemizedlist> 136 <listitem><para>Names for which synthetic records are generated (the local hostname, 137 <literal>localhost</literal> and <literal>localdomain</literal>, local gateway, as listed in the 138 previous section) and addresses configured in <filename>/etc/hosts</filename> are never routed to the 139 network and a reply is sent immediately.</para></listitem> 140 141 <listitem><para>Single-label names are resolved using LLMNR on all local interfaces where LLMNR is 142 enabled. Lookups for IPv4 addresses are only sent via LLMNR on IPv4, and lookups for IPv6 addresses are 143 only sent via LLMNR on IPv6. Note that lookups for single-label synthesized names are not routed to 144 LLMNR, MulticastDNS or unicast DNS.</para></listitem> 145 146 <listitem><para>Queries for the address records (A and AAAA) of single-label non-synthesized names are 147 resolved via unicast DNS using search domains. For any interface which defines search domains, such 148 look-ups are routed to the servers defined for that interface, suffixed with each of those search 149 domains. When global search domains are defined, such look-ups are routed to the global servers. For 150 each search domain, queries are performed by suffixing the name with each of the search domains in 151 turn. Additionally, lookup of single-label names via unicast DNS may be enabled with the 152 <varname>ResolveUnicastSingleLabel=yes</varname> setting. The details of which servers are queried and 153 how the final reply is chosen are described below. Note that this means that address queries for 154 single-label names are never sent out to remote DNS servers by default, and resolution is only 155 possible if search domains are defined.</para></listitem> 156 157 <listitem><para>Multi-label names with the domain suffix <literal>.local</literal> are resolved using 158 MulticastDNS on all local interfaces where MulticastDNS is enabled. As with LLMNR, IPv4 address lookups 159 are sent via IPv4 and IPv6 address lookups are sent via IPv6.</para></listitem> 160 161 <listitem><para>Queries for multi-label names are routed via unicast DNS on local interfaces that have 162 a DNS server configured, plus the globally configured DNS servers if there are any. Which interfaces 163 are used is determined by the routing logic based on search and route-only domains, described below. 164 Note that by default, lookups for domains with the <literal>.local</literal> suffix are not routed to 165 DNS servers, unless the domain is specified explicitly as routing or search domain for the DNS server 166 and interface. This means that on networks where the <literal>.local</literal> domain is defined in a 167 site-specific DNS server, explicit search or routing domains need to be configured to make lookups work 168 within this DNS domain. Note that these days, it's generally recommended to avoid defining 169 <literal>.local</literal> in a DNS server, as <ulink 170 url="https://tools.ietf.org/html/rfc6762">RFC6762</ulink> reserves this domain for exclusive 171 MulticastDNS use.</para></listitem> 172 173 <listitem><para>Address lookups (reverse lookups) are routed similarly to multi-label names, with the 174 exception that addresses from the link-local address range are never routed to unicast DNS and are only 175 resolved using LLMNR and MulticastDNS (when enabled).</para></listitem> 176 </itemizedlist> 177 178 <para>If lookups are routed to multiple interfaces, the first successful response is returned (thus 179 effectively merging the lookup zones on all matching interfaces). If the lookup failed on all interfaces, 180 the last failing response is returned.</para> 181 182 <para>Routing of lookups is determined by the per-interface routing domains (search and route-only) and 183 global search domains. See 184 <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry> and 185 <citerefentry><refentrytitle>resolvectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> for a 186 description how those settings are set dynamically and the discussion of <varname>Domains=</varname> in 187 <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> for a 188 description of globally configured DNS settings.</para> 189 190 <para>The following query routing logic applies for unicast DNS lookups initiated by 191 <filename>systemd-resolved.service</filename>:</para> 192 193 <itemizedlist> 194 <listitem><para>If a name to look up matches (that is: is equal to or has as suffix) any of the 195 configured routing domains (search or route-only) of any link, or the globally configured DNS settings, 196 "best matching" routing domain is determined: the matching one with the most labels. The query is then 197 sent to all DNS servers of any links or the globally configured DNS servers associated with this "best 198 matching" routing domain. (Note that more than one link might have this same "best matching" routing 199 domain configured, in which case the query is sent to all of them in parallel).</para> 200 201 <para>In case of single-label names, when search domains are defined, the same logic applies, except 202 that the name is first suffixed by each of the search domains in turn. Note that this search logic 203 doesn't apply to any names with at least one dot. Also see the discussion about compatibility with 204 the traditional glibc resolver below.</para></listitem> 205 206 <listitem><para>If a query does not match any configured routing domain (either per-link or global), it 207 is sent to all DNS servers that are configured on links with the <varname>DefaultRoute=</varname> 208 option set, as well as the globally configured DNS server.</para></listitem> 209 210 <listitem><para>If there is no link configured as <varname>DefaultRoute=</varname> and no global DNS 211 server configured, one of the compiled-in fallback DNS servers is used.</para></listitem> 212 213 <listitem><para>Otherwise the unicast DNS query fails, as no suitable DNS servers can be determined. 214 </para></listitem> 215 </itemizedlist> 216 217 <para>The <varname>DefaultRoute=</varname> option is a boolean setting configurable with 218 <command>resolvectl</command> or in <filename>.network</filename> files. If not set, it is implicitly 219 determined based on the configured DNS domains for a link: if there's a route-only domain other than 220 <literal>~.</literal>, it defaults to false, otherwise to true.</para> 221 222 <para>Effectively this means: in order to support single-label non-synthesized names, define appropriate 223 search domains. In order to preferably route all DNS queries not explicitly matched by routing domain 224 configuration to a specific link, configure a <literal>~.</literal> route-only domain on it. This will 225 ensure that other links will not be considered for these queries (unless they too carry such a routing 226 domain). In order to route all such DNS queries to a specific link only if no other link is preferred, 227 set the <varname>DefaultRoute=</varname> option for the link to true and do not configure a 228 <literal>~.</literal> route-only domain on it. Finally, in order to ensure that a specific link never 229 receives any DNS traffic not matching any of its configured routing domains, set the 230 <varname>DefaultRoute=</varname> option for it to false.</para> 231 232 <para>See 233 <citerefentry><refentrytitle>org.freedesktop.resolve1</refentrytitle><manvolnum>5</manvolnum></citerefentry> 234 for information about the D-Bus APIs <filename>systemd-resolved</filename> provides.</para> 235 </refsect1> 236 237 <refsect1> 238 <title>Compatibility with the traditional glibc stub resolver</title> 239 240 <para>This section provides a short summary of differences in the stub resolver implemented by 241 <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry> together 242 with <command>systemd-resolved</command> and the traditional stub resolver implemented in 243 <filename>nss-dns</filename>.</para> 244 245 <itemizedlist> 246 <listitem><para>Some names are always resolved internally (see Synthetic Records above). Traditionally 247 they would be resolved by <filename>nss-files</filename> if provided in 248 <filename>/etc/hosts</filename>. But note that the details of how a query is constructed are under the 249 control of the client library. <filename>nss-dns</filename> will first try to resolve names using 250 search domains and even if those queries are routed to <filename>systemd-resolved</filename>, it will 251 send them out over the network using the usual rules for multi-label name routing <footnote><para>For 252 example, if <filename>/etc/resolv.conf</filename> has <programlisting>nameserver 127.0.0.53 253search foobar.com barbar.com 254 </programlisting>and we look up <literal>localhost</literal>, <filename>nss-dns</filename> will send 255 the following queries to <filename>systemd-resolved</filename> listening on 127.0.0.53:53: first 256 <literal>localhost.foobar.com</literal>, then <literal>localhost.barbar.com</literal>, and finally 257 <literal>localhost</literal>. If (hopefully) the first two queries fail, 258 <filename>systemd-resolved</filename> will synthesize an answer for the third query.</para> 259 260 <para>When using <filename>nss-dns</filename> with any search domains, it is thus crucial to always 261 configure <filename>nss-files</filename> with higher priority and provide mappings for names that 262 should not be resolved using search domains.</para></footnote>.</para></listitem> 263 264 <listitem><para>Single-label names are not resolved for A and AAAA records using unicast DNS (unless 265 overridden with <varname>ResolveUnicastSingleLabel=</varname>, see 266 <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>). 267 This is similar to the <option>no-tld-query</option> option being set in 268 <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. 269 </para></listitem> 270 271 <listitem><para>Search domains are not used for <emphasis>suffixing</emphasis> of multi-label names. 272 (Search domains are nevertheless used for lookup <emphasis>routing</emphasis>, for names that were 273 originally specified as single-label or multi-label.) Any name with at least one dot is always 274 interpreted as a FQDN. <filename>nss-dns</filename> would resolve names both as relative (using search 275 domains) and absolute FQDN names. Some names would be resolved as relative first, and after that query 276 has failed, as absolute, while other names would be resolved in opposite order. The 277 <varname>ndots</varname> option in <filename>/etc/resolv.conf</filename> was used to control how many 278 dots the name needs to have to be resolved as relative first. This stub resolver does not implement 279 this at all: multi-label names are only resolved as FQDNs.<footnote><para>There are currently more than 280 1500 top-level domain names defined, and new ones are added regularly, often using "attractive" names 281 that are also likely to be used locally. Not looking up multi-label names in this fashion avoids 282 fragility in both directions: a valid global name could be obscured by a local name, and resolution of 283 a relative local name could suddenly break when a new top-level domain is created, or when a new 284 subdomain of a top-level domain in registered. Resolving any given name as either relative or absolute 285 avoids this ambiguity.</para></footnote></para></listitem> 286 287 <listitem><para>This resolver has a notion of the special <literal>.local</literal> domain used for 288 MulticastDNS, and will not route queries with that suffix to unicast DNS servers unless explicitly 289 configured, see above. Also, reverse lookups for link-local addresses are not sent to unicast DNS 290 servers.</para></listitem> 291 292 <listitem><para>This resolver reads and caches <filename>/etc/hosts</filename> internally. (In other 293 words, <filename>nss-resolve</filename> replaces <filename>nss-files</filename> in addition to 294 <filename>nss-dns</filename>). Entries in <filename>/etc/hosts</filename> have highest priority.</para> 295 </listitem> 296 297 <listitem><para>This resolver also implements LLMNR and MulticastDNS in addition to the classic unicast 298 DNS protocol, and will resolve single-label names using LLMNR (when enabled) and names ending in 299 <literal>.local</literal> using MulticastDNS (when enabled).</para></listitem> 300 301 <listitem><para>Environment variables <varname>$LOCALDOMAIN</varname> and 302 <varname>$RES_OPTIONS</varname> described in 303 <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> 304 are not supported currently.</para></listitem> 305 </itemizedlist> 306 </refsect1> 307 308 <refsect1> 309 <title><filename>/etc/resolv.conf</filename></title> 310 311 <para>Four modes of handling <filename>/etc/resolv.conf</filename> (see 312 <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>) are 313 supported:</para> 314 315 <itemizedlist> 316 <listitem><para><command>systemd-resolved</command> maintains the 317 <filename>/run/systemd/resolve/stub-resolv.conf</filename> file for compatibility with traditional 318 Linux programs. This file may be symlinked from <filename>/etc/resolv.conf</filename>. This file lists 319 the 127.0.0.53 DNS stub (see above) as the only DNS server. It also contains a list of search domains 320 that are in use by systemd-resolved. The list of search domains is always kept up-to-date. Note that 321 <filename>/run/systemd/resolve/stub-resolv.conf</filename> should not be used directly by applications, 322 but only through a symlink from <filename>/etc/resolv.conf</filename>. This file may be symlinked from 323 <filename>/etc/resolv.conf</filename> in order to connect all local clients that bypass local DNS APIs 324 to <command>systemd-resolved</command> with correct search domains settings. This mode of operation is 325 recommended.</para></listitem> 326 327 <listitem><para>A static file <filename>/usr/lib/systemd/resolv.conf</filename> is provided that lists 328 the 127.0.0.53 DNS stub (see above) as only DNS server. This file may be symlinked from 329 <filename>/etc/resolv.conf</filename> in order to connect all local clients that bypass local DNS APIs 330 to <command>systemd-resolved</command>. This file does not contain any search domains. 331 </para></listitem> 332 333 <listitem><para><command>systemd-resolved</command> maintains the 334 <filename>/run/systemd/resolve/resolv.conf</filename> file for compatibility with traditional Linux 335 programs. This file may be symlinked from <filename>/etc/resolv.conf</filename> and is always kept 336 up-to-date, containing information about all known DNS servers. Note the file format's limitations: it 337 does not know a concept of per-interface DNS servers and hence only contains system-wide DNS server 338 definitions. Note that <filename>/run/systemd/resolve/resolv.conf</filename> should not be used 339 directly by applications, but only through a symlink from <filename>/etc/resolv.conf</filename>. If 340 this mode of operation is used local clients that bypass any local DNS API will also bypass 341 <command>systemd-resolved</command> and will talk directly to the known DNS servers.</para></listitem> 342 343 <listitem><para>Alternatively, <filename>/etc/resolv.conf</filename> may be managed by other packages, 344 in which case <command>systemd-resolved</command> will read it for DNS configuration data. In this mode 345 of operation <command>systemd-resolved</command> is consumer rather than provider of this configuration 346 file. </para></listitem> 347 </itemizedlist> 348 349 <para>Note that the selected mode of operation for this file is detected fully automatically, depending 350 on whether <filename>/etc/resolv.conf</filename> is a symlink to 351 <filename>/run/systemd/resolve/resolv.conf</filename> or lists 127.0.0.53 as DNS server.</para> 352 </refsect1> 353 354 <refsect1> 355 <title>Signals</title> 356 357 <variablelist> 358 <varlistentry> 359 <term><constant>SIGUSR1</constant></term> 360 361 <listitem><para>Upon reception of the <constant>SIGUSR1</constant> process signal 362 <command>systemd-resolved</command> will dump the contents of all DNS resource record caches it 363 maintains, as well as all feature level information it learnt about configured DNS servers into the 364 system logs.</para></listitem> 365 </varlistentry> 366 367 <varlistentry> 368 <term><constant>SIGUSR2</constant></term> 369 370 <listitem><para>Upon reception of the <constant>SIGUSR2</constant> process signal 371 <command>systemd-resolved</command> will flush all caches it maintains. Note that it should normally 372 not be necessary to request this explicitly – except for debugging purposes – as 373 <command>systemd-resolved</command> flushes the caches automatically anyway any time the host's 374 network configuration changes. Sending this signal to <command>systemd-resolved</command> is 375 equivalent to the <command>resolvectl flush-caches</command> command, however the latter is 376 recommended since it operates in a synchronous way.</para></listitem> 377 </varlistentry> 378 379 <varlistentry> 380 <term><constant>SIGRTMIN+1</constant></term> 381 382 <listitem><para>Upon reception of the <constant>SIGRTMIN+1</constant> process signal 383 <command>systemd-resolved</command> will forget everything it learnt about the configured DNS 384 servers. Specifically any information about server feature support is flushed out, and the server 385 feature probing logic is restarted on the next request, starting with the most fully featured 386 level. Note that it should normally not be necessary to request this explicitly – except for 387 debugging purposes – as <command>systemd-resolved</command> automatically forgets learnt information 388 any time the DNS server configuration changes. Sending this signal to 389 <command>systemd-resolved</command> is equivalent to the <command>resolvectl 390 reset-server-features</command> command, however the latter is recommended since it operates in a 391 synchronous way.</para></listitem> 392 </varlistentry> 393 </variablelist> 394 </refsect1> 395 396 <refsect1> 397 <title>See Also</title> 398 <para> 399 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, 400 <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, 401 <citerefentry><refentrytitle>dnssec-trust-anchors.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>, 402 <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry>, 403 <citerefentry><refentrytitle>resolvectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, 404 <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, 405 <citerefentry project='man-pages'><refentrytitle>hosts</refentrytitle><manvolnum>5</manvolnum></citerefentry>, 406 <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>, 407 <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> 408 </para> 409 </refsect1> 410 411</refentry> 412