Disable IPv6 on Debian

Edit /etc/sysctl.conf.

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

Apply the changes.

sudo sysctl -p

Disable IPv6 on Fedora

sudo grubby --args=ipv6.disable=1 --update-kernel=ALL
sudo grub2-mkconfig -o /boot/grub2/grub.cfg

Rename network interface when using systemd-networkd

Create a udev rule at /etc/udev/rules.d/70-my-net-names.rules:

SUBSYSTEM=="net", ACTION=="add", ATTR{address}=="your-mac-address", NAME="wlan0"

Using 70-my-net-names.rules as the filename ensures the rule is ordered before /usr/lib/udev/rules.d/80-net-setup-link.rules.

Connecting to WiFi network using systemd-networkd and wpa_supplicant

Create a file at /etc/wpa_supplicant/wpa_supplicant-wlan0.conf. Use wpa_passphrase to hash the passphrase.

wpa_passphrase your-ssid your-ssid-passphrase | sudo tee -a /etc/wpa_supplicant/wpa_supplicant-wlan0.conf

Edit /etc/wpa_supplicant/wpa_supplicant-wlan0.conf:

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
update_config=1

network={
  ssid="your-ssid"
  psk="your-hashed-ssid-passphrase"
  key_mgmt=WPA-PSK
  proto=WPA2
  scan_ssid=1
}

Create a file at /etc/systemd/network/25-wlan.network:

[Match]
Name=wlan0

[Network]
DHCP=ipv4

Enable and start the network services:

sudo systemctl enable --now wpa_supplicant@wlan0.service
sudo systemctl restart systemd-networkd.service
sudo systemctl restart wpa_supplicant@wlan0.service

Check the interface status:

ip a

Use tailnet DNS and prevent DNS leaks

After the above WiFi interface is setup, disable IPv6 as per the above sections, and enable the Tailscale service.

sudo systemctl enable --now tailscaled.service
sudo tailscale up

Edit /etc/systemd/networkd/25-wlan.network again, and add the following contents:

[Match]
Name=wlan0

[Network]
DHCP=ipv4
DNS=100.100.100.100
DNSSEC=allow-downgrade

[DHCPv4]
UseDNS=no

This will tell the wlan0 interface to use Tailscale’s MagicDNS, along with DNSSEC if it is available, and not to get the nameservers from the DHCPv4 connection.