0.0.0.0 IP address is fine but I would guess that something else has changed on the network that device is on to block zero-configuration networking traffic from allowing your diagnostic software to easily connect to that device.
As others, state in their answer
0.0.0.0 is a non-routable IP address that is often used by software to bind on any IP address on all networking interfaces on a device. This basically means:
“Hey I am a piece of software and will accept any connection made to any assigned IP address on the machine I am running on.”
So if the device uses DHCP—to get its own IP address for its connected interfaces—and gets an assigned address of
22.214.171.124 then you can connect to that device at
126.96.36.199. And if that address changes to
188.8.131.52 the device will happily allow you to connect to it via
0.0.0.0 seems to be something you discovered but is not the cause of the problem. Rather, I’m my opinion, the issue you have is revealed when you state:
“I usually communicate with the system for troubleshooting purposes by setting my IPv4 IP to the same range as the local IP and then running diagnostic software.”
First, that seems odd. Why would you need to change your machine’s local IP address to connect to the VxWorks device? Shouldn’t you just connect directly to the IP address of the device?
Well, when you state this all I can think of is that the device—and the diagnostic software—might operate using some sort of zero-configuration networking setup. Meaning, the device broadcasts on the network, and the diagnostic software is designed to seek out these device broadcasts to help it connect to device without knowing the exact IP address.
This kind of “self-configuring” zero-configuration networking stuff is a convenience until it becomes a headache.
My first guess is that you can connect to the device directly if you can determine what IP address it has assigned to it. And thinking even more, I bet that the reason you could connect to it in the past—but not now—might have to do with some networking change that has blocked the ports that device’s zero-configuration networking setup is broadcasting on. What port that may be? Unsure. But if zero-configuration traffic is not being routed through the network, then that is why you can’t connect to the device and the
0.0.0.0 IP address has nothing to do with it.