Can I see received packet information on the console of the PI interface?



  • Hi I'm in the process of testing the propagation of the RAK 811 with the RAK 833. The problem is that I don't have internet access where I'm testing. My question is how can I see packets information arriving on the gateway e.g. RSSI.
    Is there a debug mode I can run to see this information?
    I know I can run sudo tail -f /var/log/syslog but this dose not tells me much of the packet quality. information.

    thank you



  • Is your gateway a RAK831 or a RAK833?



  • login to ssh and execute:
    sudo tcpdump -AUq -i lo port 1700

    where 1700 is the packet fordwarder port

    you will se data as:
    15:37:02.445791 IP localhost.50689 > localhost.1700: UDP, length 113
    E....k@.@................y...D$..'...TK.{"stat":{"time":"2018-05-21 18:37:02 GMT","rxnb":2,"rxok":2,"rxfw":2,"ackr":100.0,"dwnb":0,"txnb":0}}
    15:37:02.474150 IP localhost.1700 > localhost.50689: UDP, length 4
    E.. .m@.@..].................D$.
    15:37:05.499156 IP localhost.50689 > localhost.1700: UDP, length 198
    E.....@.@....................~...'...TK.{"rxpk":[{"tmst":3826810004,"chan":2,"rfch":0,"freq":904.300000,"stat":1,"modu":"LORA","datr":"SF9BW125","codr":"4/5","lsnr":8.0,"rssi":-67,"size":18,"data":"QKnfhAAArAUIjsN0ElTNQbmz"}]}
    15:37:05.508653 IP localhost.1700 > localhost.50689: UDP, length 4



  • Sorry is RAK 831 (typo). The answer audorva provided was real help. However when I disconnect the RAK 831 from the internet I no traffic will be forwarded as the gateway can't reach the things network router.
    Is there a way to trace the packets higher up the e.g. look at the bridge between the RAK and the Pi?



  • @audorva Thank you so much it was very helpful and I will use this command regularly. The problem is that I don't have an internet connection and if the RAK is not connected to the internet no communication takes place. I need to capture the packets arriving on the Lora interface basically sniff the packets. I'm not sure if this is possible with this setup as you need to be in promiscuous mode, I think?


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