PROFINET DCP, or Discovery and Configuration Protocol, is a Layer-2 protocol used in industrial Ethernet networks to find devices and assign basic settings such as a device name and IP-related network values. Because it operates directly on the local segment, it is useful during commissioning, replacement, and maintenance when engineers need to identify equipment quickly.
In cyber security, PROFINET DCP matters because any host on the same broadcast domain may be able to send discovery or configuration traffic. That makes it a practical target for reconnaissance, unauthorized reconfiguration, or service disruption if access is not controlled. Attackers may abuse DCP to discover assets or alter settings, while defenders reduce risk by segmenting OT networks, limiting Layer-2 access, monitoring for unusual DCP requests, and disabling the service where it is not required. Even though it is not an internet-facing protocol, weak handling of DCP can still affect availability and operational visibility.