Answer :

In the defense in depth model, the layer that relates to user devices that have accessed a network is the Endpoint layer.

1. Endpoint: This layer focuses on securing individual user devices like computers, smartphones, or tablets that connect to a network. It involves implementing security measures such as antivirus software, firewalls, and access controls on these devices to protect them from cyber threats.

By securing the Endpoint layer, organizations can reduce the risk of unauthorized access, data breaches, and malware infections that could potentially compromise the entire network. It's crucial to ensure that each user device is properly protected to maintain the overall security of the network.