NSS-RESOLVE(8)

  .SH "NAME" nss-resolve, libnss_resolve.so.2 - Provide hostname resolution via systemd-resolved.service
  .SH "SYNOPSIS"
    .PP libnss_resolve.so.2

  .SH "DESCRIPTION"

    .PP 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 host names via the systemd-resolved(8) local network name resolution service. It replaces the nss-dns plug-in module that traditionally resolves hostnames via DNS.
    .PP To activate the NSS module, add resolve 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 (but after the files or mymachines entries), right before the dns entry if it exists, followed by [!UNAVAIL=return], to ensure DNS queries are always routed via systemd-resolved(8) if it is running, but are routed to nss-dns if this service is not available.
    .PP 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.

  .SH "EXAMPLE"

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

    passwd:         compat mymachines systemd
    group:          compat mymachines systemd
    shadow:         compat
    hosts:          files mymachines resolve [!UNAVAIL=return] dns myhostname
    networks:       files
    protocols:      db files
    services:       db files
    ethers:         db files
    rpc:            db files
    netgroup:       nis

  .SH "SEE ALSO"

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