ADD to /etc/resolv.conf
nameserver 8.8.8.8
nameserver 8.8.4.4
sometimes the DNS from the ISP is not reachable, or not correctly delivered by the DHCP to fix you can add this line inside Linux or routers through ssh to add a static Nameserver
add this lines to /etc/systemd/resolved.conf
[Resolve]
DNS=8.8.8.8
FallbackDNS=8.8.4.4
restart systemd resolver by:
sudo systemctl daemon-reload && sudo systemctl restart systemd-resolved
sudo apt update: “Temporärer Fehlschlag beim Auflösen” / DNS-Problem
Temporärer Fehlschlag beim Auflösen von »archive.ubuntu.com«