The norms, rules, and principles of responsible state behaviour are not unlike firewalls and firebreaks. Firewalls and firebreaks are the first line of defence if a fire breaks out; to prevent the spread of the fire, an actual wall is erected to separate buildings or subdivide them to protect the structure of a building even if the structures on either side of the firewall collapse. It buys time, till eventually the fire is put out. Similarly, a firebreak is a gap in vegetation or other combustible material that acts as a barrier to slow or stop the progress of a wildfire. In cyberspace, both firewalls and firebreaks are important; however, a Silicon Review article argued that prevention offered by a firewall sometimes fails so a firebreak is also required: Detection and response.
Firebreaks, firewalls, and ‘windows of opportunity’ in cyber norms | ORF (orfonline.org)