BACnet IP can operate on any port including non any non default ports. BACnet default port is 47808 (or BAC0 in HEX), we have also seen 47808-47817 (or BAC0-BAC9) on many different sites. When attempting to debug BACnet IP traffic that is on a non standard you need to change the default decoding for a perpendicular port.
Instructions
- Start Wireshark
- Load or capture some BACnet packets on a non standard port
- From the "Analyse" menu select "Decode as"
- Select the non default BACnet IP udp port number in the drop down box.
- Select "BVLC" from the right hand menu.
Note: "BVLC" stands for "BACnet Virtual Link Control" and is the header to all BACnet IP messages. - Click OK
Source: Chipkin.com