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I have two virtual machines running on the same host and they are both in the same NAT Network. I started a fake bacnet device on one VM (say VM1) using the utility script volttron/scripts/scalability-testing/virtual-drivers/bacnet.py. The device started up fine. Now from another VM (say VM2) on the same host and same NAT Network I ran the scan_bacnet.py but my fake device on VM1 is not getting listed.

I verified that the ip address on the BACpypes.ini file has the correct address of the host running the scan_bacnet.py script. I also changed the address in BACpypes.ini to include subnet mask (10.0.2.15/24) still no luck.

Below is the content of my BACpypes.ini on file on VM2

[BACpypes]
objectName: Betelgeuse
address: 10.0.2.15/24
objectIdentifier: 599
maxApduLengthAccepted: 1024
segmentationSupported: segmentedBoth
vendorIdentifier: 15

This is the command I ran in VM1 to start the fake bacnet device

python bacnet.py bacnet_registry.csv 10.0.2.5

I am able to ping from one VM to another and running a tcpdump on the source VM shows that the scan_bacnet.py is sending the whois request to the other VM. Running tcpdump on the destination VM shows that the machine is receiving the whois request yet the fake bacnet device isn't receiving the whois request. What am I doing wrong?

chandrika
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1 Answers1

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You need to include the subnet mask in the virtual device command line:

python bacnet.py bacnet_registry.csv 10.0.2.5/24

Also you should check the firewall setting on both VMs. CentOS, for instance, defaults to blocking all incoming traffic. (You will still see it in the output tcpdump.) For BACnet you need to open udp port 47808 for all traffic (broadcast and direct).

Kyle Monson
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  • I am running centos VMs. what is the port I should open? – chandrika Jul 26 '16 at 20:02
  • that worked. Added the subnet mask to the command line args of bacnet.py and updated ip tables to allow UDP traffic on 47808 and now my device shows up on the scan – chandrika Jul 26 '16 at 23:37