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NSS−RESOLVE

NAME

nss-resolve, libnss_resolve.so.2 − Provide hostname resolution via systemd−resolved.service

SYNOPSIS

libnss_resolve.so.2

DESCRIPTION

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.

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.

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.

EXAMPLE

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

SEE ALSO

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

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