I'm working with a PLC S7 - 1500 and a CISCO Catalyst 2960 switch. I need to configure one of the switch ports so that only the mac address of the PLC can exchange data on it, but the switch is identifying a mac address different from the one I indicated and it doesn't allows communication. Would anyone know the origin of this address or solve this problem?

Hi Bruno 19,

PROFINET devices usually uses multiple MAC addresses. For example see the manual "CPU 1515-2 PN":

Assignment of the MAC addresses

CPU 1515‑2 PN has two PROFINET interfaces, with the first interface having two ports. The PROFINET interfaces each have a MAC address, and each of the PROFINET ports has its own MAC address. The CPU 1515‑2 PN therefore has five MAC addresses in total.

The MAC addresses of the PROFINET ports are needed for the LLDP protocol, for example for the neighborhood discovery function.

The number range of the MAC addresses is sequential. The first and last MAC addresses are printed on the rating plate on the right side of each CPU 1515‑2 PN.

Kind regards
Stefan