2. Which host is likely to be behind a firewall?

Cert Prep Penetration Testing & Ethical Hacking
1

(what is the answer pls help me i dont know the server is offline ) 2. Which host is likely to be behind a firewall?(Penetrationtesiting and ethical hacking nmap basics

2

Hi. You need to discover the hosts to get the answer.
And then you will get the answer from the findings.
Hint: 1.1 core concept
Read that part that tells you about Open, Closed and Filltered ports.
If the server is down. Skip this and return back to it later.

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Is that the first thing for a beginner should be learn as a Cyber security.