hyperreal.coffee

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 with 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.