Defence in Depth (DiD) is a cybersecurity solution that employs multiple security defences layers to protect your network data and systems from cyberattacks. These Defence in Depth layers make it difficult for cybercriminals and attackers to penetrate the outer layers. And even if attackers get past these layers, the defences layers make it difficult for them to move laterally within the enterprise network and access its sensitive data and resources. The multiple layers used in the Defence in Depth strategy to secure your internal organisation network from external attackers can be Firewalls Authentication and intrusion detection systems Secured gateways The major advantage of Defence in Depth is that even if one security layer gets compromised or a part of an enterprise security layer fails, other platforms and networks are still kept safe. Hence, these redundant security layers help ensure that a single point of failure won't make the security breach affect your network security. However, even this multilayer security strategy comes with disadvantages.