{{tag>Brouillon DNS SystemD CA}}

= Notes DNS - SystemD - systemd-resolved


== Install cache DNS

<code bash>
mkdir /etc/systemd/resolved.conf.d/
chmod 755 /etc/systemd/resolved.conf.d/
</code>

Pour RedHat 9
<code bash>
dnf install systemd-resolved
</code>

''/etc/systemd/resolved.conf.d/dns_servers.conf''
<code ini>
[Resolve]
DNS=8.8.8.8 8.8.4.4
Domains=acme.local dev.local
FallbackDNS=

# Work on RedHat 9. Before 'no-negative' is ignored, Default is 'yes'
Cache=no-negative

#StaleRetentionSec=SECONDS

# Fix bug 10 seconds timeout shortname resolution. Ex : '/usr/bin/host plop'
LLMNR=no

# Useless / not yet used
MulticastDNS=no
DNSSEC=no
DNSOverTLS=no
</code>

<code bash>
chmod 644 /etc/systemd/resolved.conf.d/dns_servers.conf

sysctemctl enable --now systemd-resolved.service

cp -p /etc/resolv.conf /etc/resolv.conf.bak
ln -sf /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf
</code>

<code bash>
systemctl status systemd-resolved

resolvectl statistics
</code>