This setup will break any DNS servers already running on your Pi, such as Pi-Hole, so make sure you know what you're getting into.
+ +You need to be root for the whole guide, so either use `sudo -Es` or `sudo su` to switch to the root user. + +First, you have to remove the "classic" networking. You can do this while connected to SSH, so don't worry. + +```bash +systemctl daemon-reload +systemctl disable --now ifupdown dhcpcd dhcpcd5 isc-dhcp-client isc-dhcp-common rsyslog +apt --autoremove purge ifupdown dhcpcd dhcpcd5 isc-dhcp-client isc-dhcp-common rsyslog +rm -r /etc/network /etc/dhcp +systemctl disable --now avahi-daemon libnss-mdns +apt --autoremove purge avahi-daemon +``` + +Next, install and set up systemd-resolved and systemd-networkd. + +```bash +apt install libnss-resolve +ln -sf /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf +apt-mark hold avahi-daemon dhcpcd dhcpcd5 ifupdown isc-dhcp-client isc-dhcp-common libnss-mdns openresolv raspberrypi-net-mods rsyslog +systemctl enable systemd-networkd.service systemd-resolved.service +``` + +### Set up wpa_supplicant as an access point. + +wpa_supplicant is what Raspbian uses for its WiFi configuration. We need to configure it to broadcast an access point that our devices can later connect to. + +First, create `/etc/wpa_supplicant/wpa_supplicant-wlan0.conf` and add the following contents: + +```conf +# /etc/wpa_supplicant/wpa_supplicant-wlan0.conf + +country=US +ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev +update_config=1 + +network={ + ssid="..." # Set to your desired network name + mode=2 + frequency=2437 # change this to 5000 if you want a 5GHz access point + #key_mgmt=NONE # uncomment this if you don't want a password + # delete next 3 lines if key_mgmt=NONE + key_mgmt=WPA-PSK + proto=RSN WPA + psk="..." # set this to your desired password +} +``` + +Your password will be stored in plain text so make sure this file is not readable by anyone you don't want seeing the password.
+ +### Setting up the bridge + +Now, we need to create a *bridge* network interface. This interface will bridge packets coming from the WiFi interface (`wlan0`) and send them over the Ethernet interface (`eth0`). This will allow devices connected to the Pi to appear on the same subnet as devices connected to the router itself. + +First, define the interface: + +```ini +; /etc/systemd/network/02-br0.netdev + +[NetDev] +Name=br0 +Kind=bridge +``` + +Then, tell `systemd-networkd` to bridge packets to `eth0`: + +```ini +; /etc/systemd/network/04-br0_add-eth0.network + +[Match] +Name=eth0 +[Network] +Bridge=br0 +``` + +Finally, configure network settings on the bridge: + +```ini +; /etc/systemd/network/12-br0_up.network + +[Match] +Name=br0 +[Network] +MulticastDNS=yes +DHCP=yes +``` + +### Tell wpa_supplicant to use a bridge + +Now we have our bridge configured, but we need to tell our WiFi interface to actually use it. To do this, edit the `.service` file: + +```bash +systemctl edit wpa_supplicant@wlan0.service +``` + +This will open up your editor. In this editor add these lines: + +```ini +[Service] +ExecStartPre=/sbin/iw dev %i set type __ap +ExecStartPre=/bin/ip link set %i master br0 + +ExecStart= +ExecStart=/sbin/wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant-%I.conf -Dnl80211,wext -i%I -bbr0 + +ExecStopPost=-/bin/ip link set %i nomaster +ExecStopPost=-/sbin/iw dev %i set type managed +``` + +### Epilogue + +Finally, reboot. That's it! Your shiny new network extender should appear in the list of local WiFi networks. Connect to it, and see the difference! + +If you have any questions, feel free to [shoot me an email](mailto:yash@karx.xyz)! + +