Security starts with the cables, ports and switches carrying your traffic. A...

https://blast-wiki.win/index.php/How_to_Separate_OT_and_IT_Networks_with_VLANs

Security starts with the cables, ports and switches carrying your traffic. A damaged patch lead can stop VPN handshakes, while poor switch setup can give intruders a way in. See why the physical network deserves the same care as the systems it connects.