RUT301 - Profinet doesn't work, VPN problems

NETWORKING SOLUTIONS
1

Hello everyone,

I’m currently setting up an industrial network with a new Teltonika RUT301 and have run into a couple of issues. I’m hoping someone can point me in the right direction.

My network setup includes:

  • A Windows PC

  • Siemens S7-1200 G2 PLC

  • Kuka Robot with a KRC5 controller

  • Several other Profinet devices

All devices have static IP addresses within the same subnet.

## Problem 1: Profinet Device Discovery

When all devices are connected to the RUT301’s LAN ports, I can successfully ping every single device from the Windows PC. This confirms basic IP connectivity is working fine.

However, the S7-1200 PLC is unable to see or discover the other Profinet devices on the network. When I swap the RUT301 for a simple, unmanaged switch or a different basic router, the Profinet communication works perfectly and the PLC finds all devices immediately. This leads me to believe a setting on the RUT301 is blocking the specific Layer 2 traffic that Profinet uses for discovery (EtherType 0x8892).

My question is: Is there a specific firewall setting, multicast/IGMP snooping option, or another feature on the RUT301 that needs to be configured to allow Profinet’s Layer 2 discovery frames to pass between the LAN ports?

## Problem 2: Transparent VPN for Full LAN Access

Once the Profinet issue is solved, my next goal is to establish remote access to this entire LAN.

I need a VPN solution that makes my remote computer behave as if it were physically plugged into a LAN port on the router. I need to be able to use industrial software (like Siemens TIA Portal) which relies on network scans and Layer 2 discovery to find and connect to devices.

I want to avoid having to configure access to each device individually in RMS. The ideal scenario is connecting to the VPN and instantly having full, transparent access to the entire subnet, including any new devices that might be added later. This is the functionality I’m used to with other systems like IXON.

My question is: Does the RUT301 support a “bridged” (TAP/Layer 2) OpenVPN setup that would provide this level of transparent access? If so, could you provide any guidance? Or is there another recommended method using the Teltonika ecosystem to achieve this “virtual network cable” type of connection?

Thank you in advance for any help or advice you can offer!

9

Hello,

Thank you for reaching out.

  1. Regarding Profinet device discovery:

Normally, Profinet communication should work transparently through the RUT301 without additional configuration, but there are two points worth checking:

  • If your router is running an older firmware, please update to the latest version, as starting with RutOS 7.8 there were some changes related to Profinet support and handling.
  • In similar cases, setting the LAN interface VLAN ID to 0 instead of 1 has resolved Profinet discovery issues. This can be done via WebUI, e.g.,:
    image
    image1349×259 12.8 KB

    (set only on LAN port 2)
  1. Regarding OpenVPN in TAP/bridge mode setup:

Yes, the RUT301 supports OpenVPN in TAP (Layer 2) mode. You can find a detailed setup guide here:

Best regards,