# How to check the operating system of a server remotely?

Is there a tool that takes an IP address and outputs the operating system of that machine?

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I don't think any such tool to determine OS type solely from IP address exists. nmap could give you its best guess. –  jw013 Jul 23 '12 at 12:33
I'm sorry. should have searched better. superuser.com/questions/164193/… –  minerals Jul 23 '12 at 12:39

Yes, it's called nmap. Keep in mind that you should have permission from the owner of the remote system before running tools like this against it.

nmap -O

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Kind of. nmap will take its best guess. It's usually fairly accurate but it can be wrong. It's impossible to tell with 100% accuracy. –  bahamat Jul 23 '12 at 15:25

You can use tools like nmap to do this. However, make sure you know the local laws before running a tool like nmap. It is prohibited to use such tools without the explicit permission of the network administrator even on your office network.

nmap -O


The -O option does operating system “fingerprinting”. Nmap version 5.50 has 2,982 OS fingerprints and 7,319 version-detection signatures.