1NSS-RESOLVE(8)                    nss-resolve                   NSS-RESOLVE(8)
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NAME

6       nss-resolve, libnss_resolve.so.2 - Hostname resolution via
7       systemd-resolved.service
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SYNOPSIS

10       libnss_resolve.so.2
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DESCRIPTION

13       nss-resolve is a plug-in module for the GNU Name Service Switch (NSS)
14       functionality of the GNU C Library (glibc) enabling it to resolve
15       hostnames via the systemd-resolved(8) local network name resolution
16       service. It replaces the nss-dns plug-in module that traditionally
17       resolves hostnames via DNS.
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19       To activate the NSS module, add "resolve [!UNAVAIL=return]" to the line
20       starting with "hosts:" in /etc/nsswitch.conf. Specifically, it is
21       recommended to place "resolve" early in /etc/nsswitch.conf's "hosts:"
22       line. It should be before the "files" entry, since systemd-resolved
23       supports /etc/hosts internally, but with caching. To the contrary, it
24       should be after "mymachines", to give hostnames given to local VMs and
25       containers precedence over names received over DNS. Finally, we
26       recommend placing "dns" somewhere after "resolve", to fall back to
27       nss-dns if systemd-resolved.service is not available.
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29       Note that systemd-resolved will synthesize DNS resource records in a
30       few cases, for example for "localhost" and the current local hostname,
31       see systemd-resolved(8) for the full list. This duplicates the
32       functionality of nss-myhostname(8), but it is still recommended (see
33       examples below) to keep nss-myhostname configured in
34       /etc/nsswitch.conf, to keep those names resolveable if systemd-resolved
35       is not running.
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37       Please keep in mind that nss-myhostname (and nss-resolve) also resolve
38       in the other direction — from locally attached IP adresses to
39       hostnames. If you rely on that lookup being provided by DNS, you might
40       want to order things differently.
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42       Communication between nss-resolve and systemd-resolved.service takes
43       place via the /run/systemd/resolve/io.systemd.Resolve AF_UNIX socket.
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EXAMPLE

46       Here is an example /etc/nsswitch.conf file that enables nss-resolve
47       correctly:
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49           passwd:         compat systemd
50           group:          compat [SUCCESS=merge] systemd
51           shadow:         compat systemd
52           gshadow:        files systemd
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54           hosts:          mymachines resolve [!UNAVAIL=return] files myhostname dns
55           networks:       files
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57           protocols:      db files
58           services:       db files
59           ethers:         db files
60           rpc:            db files
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62           netgroup:       nis
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SEE ALSO

65       systemd(1), systemd-resolved(8), nss-systemd(8), nss-myhostname(8),
66       nss-mymachines(8), nsswitch.conf(5)
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70systemd 249                                                     NSS-RESOLVE(8)
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