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Our KNX interface is using KNXnet/IP tunneling to communicate to the KNX network. Therefore, any standard conform KNXnet/IP router or interface can be used.

Within the Item Tree of the server, a so called "Gateway Item" shows the connection state to a KNXnet/IP router or interface. If it is true, the connection is working – if it is false a communication problem exist. The following figure shows an example where the connection to a

KNXnet/IP router is successfully established.

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In addition, a "Status Item" provides an error code if the connection is not working:

  • 1000: this indicates a network problem. The server is not able to establish an IP connection to router or interface. Please check your firewall, network and all network switches and routers.
  • 36: this indicates that no KNXnet/IP tunneling connection is available. A KNXnet/IP router or interface only supports a limited amount of simultaneous connections. Old devices only one – newer devices (like our NETx KNX IP Router and Interface) up to 5. Please check whether other client (e.g. ETS) is also connected to the router or interface.
  • 37: this indicates that there is no free KNX individual address available for the tunneling connection. Please check your ETS project whether all available tunneling connections are assigned to a KNX individual address. For older KNXnet/IP routers or interfaces, additional addresses may be activated by pressing the programming button for at least 5 seconds. Please check the datasheet of your device.
  • 39: the KNX connection to the router or interface is not working. Please check the twisted pair side of your router or interface.

If the status is 1000, a network problem exist. Further analyze the problem, please your firewall, network and all network switches and routers. KNXnet/IP tunneling is using UDP/IP for communication – the UDP is 3671. Please ensure that a UDP communication with port 3671 is possible between the server and the KNXnet/IP router or interface.

For analyzing the network, please do not use the "ping" command. ping uses the ICMP protocol. This means that even a ping is successful it does not indicate that a UDP/IP connection is possible. Even more each standard network device will reply to ping requests – even if it is not a KNXnet/IP router or interface.

For a meaningful analyzes you can use the following tools:

  • Wireshark: Wireshark is a very sophisticated, free network monitoring tool. Using Wireshark, you can sniff all incoming and outgoing network packets. Since 2016, Wireshark also includes a KNXnet/IP decoder.
  • nxaKNXnetIPTestTool.exe: this is a small console application which is included within the setup of the server. It can be used to test KNXnet/IP tunneling connections.

The nxaKNXnetIPTestTool.exe Tool is located within the following directory:

<installation directory>\Tools\KNXnetIP

It has the following parameters:

Usage: <Dst IP Address> [Src IP Address]

To use the tool, open a Windows "cmd" shell and change to the directory mentioned above. Then invoke the command with the IP address of the KNXnet/IP router or interface as parameter that you would like to test. The second parameter is the local IP address which is optional.

To check the router if the IP address, the following command has to be entered:

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Within the output of the  command, the raw KNXnet/IP packets are shown. In addition, it is shown whether the connection was successful – if not the error code is shown too.

Article is valid for the following products:

  • NETx BMS Platform
  • NETx Multi Protocol Server
  • NETx BMS Server 2.0

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PLATFORM:How to check the connection to a KNXnet/IP router or interface