nss-resolve(8) — Linux manual page


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

NAME         top

       nss-resolve, libnss_resolve.so.2 - Hostname resolution via

SYNOPSIS         top


DESCRIPTION         top

       nss-resolve is a plug-in module for the GNU Name Service Switch
       (NSS) functionality of the GNU C Library (glibc) enabling it to
       resolve hostnames via the systemd-resolved(8) local network name
       resolution service. It replaces the nss-dns plug-in module that
       traditionally resolves hostnames via DNS.

       To activate the NSS module, add "resolve [!UNAVAIL=return]" to
       the line starting with "hosts:" in /etc/nsswitch.conf.
       Specifically, it is recommended to place "resolve" early in
       /etc/nsswitch.conf's "hosts:" line. It should be before the
       "files" entry, since systemd-resolved supports /etc/hosts
       internally, but with caching. To the contrary, it should be after
       "mymachines", to give hostnames given to local VMs and containers
       precedence over names received over DNS. Finally, we recommend
       placing "dns" somewhere after "resolve", to fall back to nss-dns
       if systemd-resolved.service is not available.

       Note that systemd-resolved will synthesize DNS resource records
       in a few cases, for example for "localhost" and the current local
       hostname, see systemd-resolved(8) for the full list. This
       duplicates the functionality of nss-myhostname(8), but it is
       still recommended (see examples below) to keep nss-myhostname
       configured in /etc/nsswitch.conf, to keep those names resolveable
       if systemd-resolved is not running.

       Please keep in mind that nss-myhostname (and nss-resolve) also
       resolve in the other direction — from locally attached IP
       addresses to hostnames. If you rely on that lookup being provided
       by DNS, you might want to order things differently.

EXAMPLE         top

       Here is an example /etc/nsswitch.conf file that enables
       nss-resolve correctly:

           passwd:         compat systemd
           group:          compat [SUCCESS=merge] systemd
           shadow:         compat systemd
           gshadow:        files systemd

           hosts:          mymachines resolve [!UNAVAIL=return] files myhostname dns
           networks:       files

           protocols:      db files
           services:       db files
           ethers:         db files
           rpc:            db files

           netgroup:       nis

SEE ALSO         top

       systemd(1), systemd-resolved(8), nss-systemd(8),
       nss-myhostname(8), nss-mymachines(8), nsswitch.conf(5)

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
       a bug report for this manual page, see
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2021-08-27.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2021-08-27.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

systemd 249                                               NSS-RESOLVE(8)

Pages that refer to this page: nss-myhostname(8)nss-mymachines(8)nss-systemd(8)systemd-resolved.service(8)