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I've discovered that even if you block tcp/udp/icmp input and output to and from a host you can still port scan that host and find out it's open ports. I'm ...
  1. 10-14-2009 #1
    muton
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    defeating nmap -PN

    I've discovered that even if you block tcp/udp/icmp input and output to and from a host you can still port scan that host and find out it's open ports. I'm assuming this means that that host can still do the same to me. Is there a way to block port scanners like this so I know that they can't see me online?

    also, how else can i be seen as online, with tcp/udp/icmp blocked?
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  2. 10-15-2009 #2
    GNU-Fan
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    Quote Originally Posted by muton View Post
    also, how else can i be seen as online, with tcp/udp/icmp blocked?
    Because you are known to other network nodes.
    Imagine the police asking your neighbourhood questions about you and showing everybody a picture of you. Finally you will be found, no matter if you answer the doorbell or not.
    Debian GNU/Linux -- You know you want it.
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  3. 10-18-2009 #3
    muton
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    i see, thanks.
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