What is the format of the heartbeat packet sent by the DIGI WR-21?

I’ve configured my DIGI WR21 to send a heartbeat packet periodically to a server that I run. I can see the heartbeat packet coming from the router to my server using Wireshark, but am interested in the format of the data. I cannot find any documentation on DIGI’s website about the organization of the payload in this UDP packet. Can anyone help?


What type of heartbeat are you referring too? Typically these are just typical Internet Control Message Protocol (ICMP).

Can you provide an example or location on where you are configuring this?

Under Configuration - Network > Interfaces > Advanced > PPP 1 > Advanced is the option “Generate Heartbeat packets on this interface”. These are UDP packets that can be directed to a particular IP address.