A peer-to-peer link is a direct connection between devices, where traffic moves from one endpoint to another without first passing through a central server. On mobile platforms, this can be built with local wireless features such as Bluetooth, Wi-Fi Direct, or other device-discovery and short-range transport mechanisms. Because the connection is local and often legitimate-looking, it can be harder to monitor than normal internet traffic.
In cyber security, peer-to-peer links matter because attackers can use them as a backup channel for command, control, or data exfiltration. If outbound internet access is blocked, malware may relay data through a nearby infected device instead of sending it directly to a remote server. Defenders should watch for unusual nearby-device discovery, unexpected local radio activity, and apps requesting permissions they do not obviously need. Monitoring only firewalls, DNS, or web proxies can miss this kind of lateral communication.