Smart Recon uses a combination of discovery scanning and reconnaissance tools to determine (with maximum accuracy) which of your targets are Active and which are Unresponsive.

You'll know within seconds of adding your targets whether they're active or not. This information can be used to determine exactly how many licenses you need (after all, you don't want to spend money scanning targets that aren't exposed to the internet).

It'll also tell you which of your targets are unresponsive, in case that's not what you're expecting:
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Simply head to the Targets page > click 'Add Target':

In the pop-up window, you have the option to add a target or target range (via IP address subnet CIDR notation or by importing a CSV (Comma Separated Values) file):
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Depending on the button and your target's status, you'll see one of the following:

Advice for troubleshooting unresponsive hosts can be found here: