When configured to do so, Foreman uses the Puppet facts to declare network interfaces which is pretty convenient, especially when handled hosts get declared via a Puppet run.
The thing is that, with machines having dynamic interfaces (say hypervisors with net tap or bridges), network list keeps growing over time.

It would be nice to remove network interfaces declared in Foreman that are not present in the Puppet facts.
Also, avoid adding duplicate entries with the same name (multiple eth0 entries with different mac, ipaddress).