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73 views

Does Nmap requires a closed TCP port to do OS fingerprinting?

I was checking the security of a server by running Nmap. Last time it gives me the following results, indicating that OS could not be fingerprinted: PORT STATE SERVICE VERSION 21/tcp ...
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3answers
879 views

How to find the OS of the target machine

I am new to this field. Currently I am using Linux OS and my question is how can I find the OS of another machine to which I do not have a direct access. I am interested in any possibilities which ...