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Am Donnerstag, 8. Januar 2004 13:06 schrieb mir gonzalo: |
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> 1/8/04 8:50 AM, Oliver Schad escribio: |
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> > Am Mittwoch, 7. Januar 2004 23:05 schrieb mir Mark Hurst: |
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> >> It's much better to have a firewall than just have ports not open. |
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> >> Even though a port is not open it can reveal the presence of your |
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> >> machine by the manner in which the IP stack responds to a connection |
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> >> attempt. Using a firewall you can drop those packets, making all |
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> >> your closed ports invisible. |
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> > |
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> > If you want to invisible, the next router to you have to send an ICMP |
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> > packet with "host unreachable". If you say nothing anybody with some |
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> > brain between his ears knows there is a very intelligent guy that |
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> > want to be invisible. |
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> |
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> AFAIK they appear as "filtered",that's the difference between a closed |
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> and a filtered port. The first responds with a "negative", the second |
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> doesn't respond. Am I wrong? |
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That's right. But no answer means there is somebody who doesn't answer. |
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Only if the last router before the target says "Hey, there is nobody", |
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then there is nobody (or there is an really intelligent guy, that wants |
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to hide his host). |
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To hide a host is always very stupid, why should you do this? There is no |
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advantage. If you "hide" your computer an attacker knows there is an |
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stupid guy who doesn't know anything about network security. |
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|
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mfg |
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Oli |
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|
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-- |
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