Run dhcp on all ethernet devices
My laptop doesn't have a built-in ethernet controller (WiFi only). I want all Ethernet devices to be dhcp-ed automatically, as soon as they appear (USB tethering phone, USB-to-ethernet adaptor). But I don't want to mess up the configuration for my WiFi card.
/usr/lib/systemd/system/dhcpcd.service (Arch Linux)
[Unit] Description=dhcpcd on all en* interfaces Wants=network.target Before=network.target [Service] Type=forking PIDFile=/run/dhcpcd/pid # Only allow ethernet devices, ignore unrenamed devices as udev # will (try to) rename them whilst dhcpcd is fiddling with them ExecStart=/usr/bin/dhcpcd -q -b --allowinterfaces 'en*' --denyinterfaces 'eth*' ExecStop=/usr/bin/dhcpcd -x [Install] WantedBy=multi-user.target
Put this in
/etc/systemd/system/dhcpcd-all-en.service and run
systemctl daemon-reload systemctl enable --now dhcpcd-all-en