The PROFINET stacks do not use the configured Ethernet adapters of the PLC exclusively. The PROFINET protocols run parallel with the network protocols (for example, UDP), as well as building on these. In this way, these Ethernet adapters can also be used for CODESYS communication. However, the firewall configuration (if active) must be modified to the PROFINET requirements.
Network protocols used
PROFINET RT (Ethertype = 0x8892)
UDP, Port 0x8894, as well as free ports in the range of 0xC000 – 0xFFFF ( – 0xC0FF is usually sufficient).
Also for incoming packages.
LLDP (Ethertype 0x88CC)
ARP (Ethertype 0x0806)
It is usually sufficient to unblock the UDP ports at the firewall.
The PROFINET-RT protocol is not an IP protocol. It cannot be routed and it is limited to the local network.
Note: If you suspect that the firewall is the cause of the communication problems, then deactivate it temporarily in an isolated environment.
