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NAME | SYNOPSIS | DESCRIPTION | EXAMPLE | SEE ALSO | COLOPHON |
NSS-RESOLVE(8) nss-resolve NSS-RESOLVE(8)
nss-resolve, libnss_resolve.so.2 - Hostname resolution via
systemd-resolved.service
libnss_resolve.so.2
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 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.
Here is an example /etc/nsswitch.conf file that enables nss-resolve
correctly:
passwd: compat systemd
group: compat systemd
shadow: compat
hosts: mymachines resolve [!UNAVAIL=return] myhostname files dns
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis
systemd(1), systemd-resolved(8), nss-systemd(8), nss-myhostname(8),
nss-mymachines(8), nsswitch.conf(5)
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
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2020-08-13. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2020-08-11.) 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 man-pages@man7.org
systemd 246 NSS-RESOLVE(8)
Pages that refer to this page: 30-systemd-environment-d-generator(7) , systemd.directives(7) , systemd.index(7) , libnss_myhostname.so.2(8) , libnss_mymachines.so.2(8) , libnss_systemd.so.2(8) , nss-myhostname(8) , nss-mymachines(8) , nss-systemd(8) , systemd-resolved(8) , systemd-resolved.service(8)