To delete the DNS cache on most used Linux distributions, the commands will vary depending on the distribution and version:
Ubuntu 14.04 (Trusty Tahr)
Ubuntu 14.04 uses dnsmasq as the DNS resolver. To clear the DNS cache, you can restart the dnsmasq service:
sudo service dnsmasq restart
Ubuntu 16.04 (Xenial Xerus)
Ubuntu 16.04 uses systemd-resolved as the DNS resolver. To clear the DNS cache, you can restart the systemd-resolved service:
sudo systemctl restart systemd-resolved
Ubuntu 18.04 (Bionic Beaver)
Ubuntu 18.04 also uses systemd-resolved. The command to clear the DNS cache remains the same:
sudo systemctl restart systemd-resolved
Ubuntu 20.04 (Focal Fossa) and Later
Ubuntu 20.04 and later versions continue to use systemd-resolved. To clear the DNS cache, you can use the following command:
sudo systemctl restart systemd-resolved
AlmaLinux 7
AlmaLinux 7 uses nscd (Name Service Cache Daemon) for DNS caching. To clear the DNS cache, you can restart the nscd service:
sudo systemctl restart nscd
If you are using dnsmasq for DNS caching, you can restart the dnsmasq service:
sudo systemctl restart dnsmasq
AlmaLinux 8
AlmaLinux 8 uses systemd-resolved for DNS caching. To clear the DNS cache, you can restart the systemd-resolved service:
sudo systemctl restart systemd-resolved
If you are using nscd for DNS caching, you can restart the nscd service:
sudo systemctl restart nscd
AlmaLinux 9
AlmaLinux 9 continues to use systemd-resolved for DNS caching. The command to clear the DNS cache remains the same:
sudo systemctl restart systemd-resolved
Debian 7 (Wheezy)
Debian 7 uses nscd (Name Service Cache Daemon) for DNS caching. To clear the DNS cache, you can restart the nscd service:
sudo service nscd restart
Debian 8 (Jessie)
Debian 8 also uses nscd for DNS caching. The command to clear the DNS cache remains the same:
sudo service nscd restart
Debian 9 (Stretch)
Debian 9 uses systemd-resolved for DNS caching. To clear the DNS cache, you can restart the systemd-resolved service:
sudo systemctl restart systemd-resolved
If you are using nscd for DNS caching, you can restart the nscd service:
sudo systemctl restart nscd
Debian 10 (Buster)
Debian 10 continues to use systemd-resolved for DNS caching. The command to clear the DNS cache remains the same:
sudo systemctl restart systemd-resolved
If you are using nscd for DNS caching, you can restart the nscd service:
sudo systemctl restart nscd
Debian 11 (Bullseye) and Later
Debian 11 and later versions continue to use systemd-resolved. To clear the DNS cache, you can use the following command:
sudo systemctl restart systemd-resolved
If you are using nscd for DNS caching, you can restart the nscd service:
sudo systemctl restart nscd
Rocky Linux 7
Rocky Linux 7 uses nscd (Name Service Cache Daemon) for DNS caching. To clear the DNS cache, you can restart the nscd service:
sudo systemctl restart nscd
If you are using dnsmasq for DNS caching, you can restart the dnsmasq service:
sudo systemctl restart dnsmasq
Rocky Linux 8
Rocky Linux 8 uses systemd-resolved for DNS caching. To clear the DNS cache, you can restart the systemd-resolved service:
sudo systemctl restart systemd-resolved
If you are using nscd for DNS caching, you can restart the nscd service:
sudo systemctl restart nscd
Rocky Linux 9
Rocky Linux 9 continues to use systemd-resolved for DNS caching. The command to clear the DNS cache remains the same:
sudo systemctl restart systemd-resolved
If you are using nscd for DNS caching, you can restart the nscd service:
sudo systemctl restart nscd