I would to configure the Ethernet port to behave as follows:
1) check via DHCP if connected to router and receive LAN IP assignment
2) fallback to IP=192.168.1.20 GATEWAY=192.168.1.88 when directly connected to laptop Ethernet port.
QUESTIONS
a) Is there an example of where this has already been done?
b) Does it make sense to have crontab do this or is there an easier way?
Thank you for considering the questions. I look forward to suggestions / clarifying questions.