Does the probe have an Ethernet by-pass and in event the device has failed or being power off, it will just be a pass thru without affecting the network?

Yes, the hardware probe does come with Ethernet by-pass feature that ensure traffic pass thru when the probe failed or is powered off.

However, please note that Ethernet by-pass is not available for Sinefa Virtual Appliance.

For more details on the differences between Physical and Virtual Appliance. Do check out the following video