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JoelBender / bacpypes

BACpypes provides a BACnet application layer and network layer written in Python for daemons, scripting, and graphical interfaces.
MIT License
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Connecting to Router in other network #132

Open ghost opened 7 years ago

ghost commented 7 years ago

Hi,

I am trying to connect to a BACnet device behind a BACnet router behind a router:

My PC is in network A. I only can send (unicast) packages to network B, Adress 192.168.0.4, and only UDP 47808. Adress 192.168.0.4 is a BACnet/IP to BACnet/LONtalk router (device ID 10), which routes to device 20. Broadcasts are dropped in the firewall.

So far, I am only able to use "whois 192.168.0.4" (from the WhoIsIAm.py example) to contact device 10 and get a response.

When using a maintaince acess directly to network 192.168.0.0 I can use Yabe to send out a WhoIs and find both device 10 and device 20, Yabe listing the adress (1 1 via 192.168.0.4) for device 20.

Do you have any idea how to make this work?

Best regards

JoelBender commented 7 years ago

Your description is missing network numbers, so I'm going to assume that your PC is 192.168.0.3 on BACnet network 2, and your router routes between 192.168.0.4 on network 2 and address 99 on network 1. Your mission is to send a read request to address 1 on network 1.

If you are running the ReadProperty.py application and just say read 1:1 device 20 objectName it is going to attempt to find the router to network 1, which you mention is blocked (probably because reading a property uses a confirmed service, and confirmed services shouldn't be broadcast). There is a rtn command which you can use to tell the network layer of your application where to find the router to the destination network, rtn 192.168.0.4 1 will add that into the local routing tables cache.

After that your read will "magically" become a unicast message on the BACnet/IP network, and then be a unicast message on the LONtalk network.

JoelBender commented 7 years ago

I'd be curious to see what the output of the WhoIsRouter.py sample application if you put in irt 192.168.0.4 to get the router to dump its routing table, and wirtn * 1 to send a local broadcast Who-Is-Router-To-Network and see it respond.

ghost commented 7 years ago

Hello,

thank you for your reply. Following you first post I could not get a response from either device. The wirtn command send out an ICMP broadcast which was blocked at the firewall.

irt send out a package and recieved an Ack from device 10, but it did not do anythign else I could see.

I appreciate your help. Unfortunatly I will be out of office for a few weeks. After that I will try your proposed method again and get back to you.

Thank you.