19.2.3. Ethernet Configuration

The Raspberry Pis are connected with each other via Ethernet. To have a flexible solution, we define a fallback profile in /etc/dhcpcd.conf. So in case you connect the Raspberry Pi directly to the Router, it uses DHCP. If no DHCP server is available, the Raspberry Pis use the static IP address defined in the fallback profile.

Either uncomment the existing lines or add them, so dhcpcd.conf contains the following:

# It is possible to fall back to a static IP if DHCP fails:
# define static profile
profile static_eth0
static ip_address=10.0.0.1/24

# fallback to static profile on eth0
interface eth0
fallback static_eth0

You might want to restart the Raspberry Pis.