I have been fooling around with the iptables on my Slackware Linux box, and when I set it to DENY inbound and forward traffic, and ACCEPT all outbound traffic, I could not portscan my computer. There are some issues with this, though. ping does not work, so you would have to explicitly allow echo-reply, destination-unreachable, and time-exceded ICMP inbound packets. Of course, if you wanted to ssh into your box, or run a webserver, or something of that sort, you would have to explicitly allow these connections as well.
I found the information on iptables in its man page, and at http://tldp.org/HOWTO/Security-Quickstart-HOWTO/index.html
This is what I have been able to figure out in about a week's worth of playing around with iptables and nmap. Someone who has a lot more experience with either or both is welcome to tear apart my method or add some constructive criticism.
CJH
On Friday, Feb 7, 2003, at 09:43 US/Eastern, Prathap R wrote:
hello all,
i just used nmap to detect the os on the network. out of curiosity,i want to know if there is a way of making the OS undetectable. it will be of great help if anyone could point out how do it?. i am using both windows and linux.
thanks in advance.
regards,
Prathap
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