Network configuration

Address configuration

The student Raspberry Pis and the virtual machine try getting an IPv4 address on their ethernet adapter via DHCP.

The simplest setup is to connect them all to a simpler consumer router that hands out IP addresses from a pool.

Each Raspberry Pi will, in addition, run an isolated network on the WiFi interface on which it gives out IP addresses using DHCP.

Clients connected to that network can not access the internet, the other Raspberry Pis, or the cloud server.


The network is condigured using systemd-networkd in the configuration files in /etc/system/network.

The WiFi setup is done using hostapd. The WiFi interface can not be used to connect to wireless networks.


The old ifconfig line of tools are deprecated, use for example ip addr to show the IP addresses assigned to you network interfaces.

DNS

The Raspberry Pis and the virtual machine get assigned their DNS server to use using DHCP.

It is not assumed that custom domain names can be added to the zones of that DNS server. In order to get human-readable names for e.g. the nota-cloud virtual machine LLMNR is used, which sends DNS requests to the whole subnet using multicast packets and the corresponding host answers with its IP address.

This will not work if the virtual machine and the Pis are not in the same multicast domain (≈ separated by a router). The you will have to configure DNS to resolve the domain name of the cloud server and generate an appropriate server certificate.

Internet Access

Also the Lab is mostly self contained there are reasons to give internet access to the Raspberry Pis and virtual machine, namely:

  • The Raspberry Pis do not contain a real time clock, they need access to an NTP server to get the correct time. The server certificates can appear invalid when the the time is wrong.
  • The students should be able to look up programming ressources while working.