Im concerned if I am scanning effectively.

When I scan our external IP's with the scanner on my laptop the packets are leaving my network through my firewall and routing across the internet to hit my public IP's. If this can be done why would I need to pay extra for a "cloud\external scanner" if I can just do it from my laptop. Am I not seeing the external IP's the same as if I were an outsider?

  • You haven’t explained your network architecture so it’s difficult to answer. Are you scanning from a laptop within the network? Or are you at home, for example, using your laptop to scan an external IP?
    Aug 22, 2019 at 19:58
  • Or do you mean your public IPs are those on a public cloud service? If so you MUST make sure you are authorised to scan them. If that’s the case they are NOT your IPs.
    Aug 22, 2019 at 20:00
  • Im scanning from a laptop within the network
    – errMSG
    Aug 22, 2019 at 20:06
  • 1
    And what IP are you scanning? If it’s the public IP then you may not be routing out, depends how the routing is configured. You ideally want to scan public IPs from outside of the network if you are not fully sure as to what you are doing. But make sure you have authority to do so.
    Aug 22, 2019 at 20:08
  • 1
    In essence yes. But it’s more a routing issue
    Aug 22, 2019 at 20:12

1 Answer 1


It depends most on how your network is configured, or if the target employs geoblocking or not.

If your firewall allows the sending of arbitrary packets, even malformed ones, and the target does not care if you are in Ireland or Argentina, a cloud-based scanner works the same as using your own IP.

On the other hand, if your firewall "sanitizes" packets, discarding malformed ones, or your target drops packets depending on your location, it can be worth pay for a cloud scanner. How a target handles malformed packets are a good indicator of OS used, application running and so on. If your firewall "fixes" the packets, that can mask your results.

Another consideration is technical support. Commercial cloud scanners will usually offer help if you run into problems, and help interpret results. If you are skilled enough to do a scan without assistance, that may be unnecessary.

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