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I am performing a port scanning with NMAP from my laptop to some public services on Internet... I am using a VPN service, therefore my port scanning goes through VPN server and later hits the machines running the services.

|Laptop(NMAP)| <===[VPN]====> |VPN_Server| <====[uncyphered connection]=====> |Public service|

My question is... may the machine in which I am performing the port scanning disclose my public IP address (laptop) if I do this?

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closed as off-topic by joeqwerty, faker, Sven, squillman, EEAA Sep 7 '13 at 21:29

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions must be relevant to professional system administration. Server Fault is a site dedicated to professionals; novice questions are off-topic. Please see the Help Center for more information on topicality. The best advice we can give you is to hire a professional to help you out." – joeqwerty, faker, Sven, squillman, EEAA
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If you describe the target of your portscan as victim and fear to be exposed, STOP IT NOW, as you are being an asshole. – Sven Sep 7 '13 at 20:25
I am only trying to explain the scenario. It is not a real scenario and I am not a hacker, I am only trying to learn. – Cristian Yebra Sep 7 '13 at 20:28
up vote 1 down vote accepted

While the VPN tunnel, and potentially one or more NAT gateways is masking your source address, that doesn't mean your not leaving fingerprints in the data being transmitted.

So... to answer your question, will they likely see it on the layer 3 headers of the received packets? Most likely no. Is there potentially other data included that might compromise the source (you)? Yes.

Why not sniff your own outbound traffic and find out? :)

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