[ no network ] --> [ Is there an IP address? ]

[ Is there an IP address? ] -- no --> [ Check NIC driver, dmesg ]

[ Is there an IP address? ] -- yes --> [ Can you ping the router? ]

[ Can you ping the router? ] -- no --> [ Check cables, router, and switches ]

[ Can you ping the router? ] -- yes --> [ Can you ping a DNS address? ]

[ Can you ping a DNS address? ] -- no --> [ Trying pinging 8.8.8.8 ]

[ Can you ping a DNS address? ] -- yes --> [ Traceroute ]