#nmap -sF 192.168.1.10
Starting nmap 3.20 ( www.insecure.org/nmap/ ) at 2003-03-19 09:07 PST
Interesting ports on system.foobar.com (192.168.1.10):
(The 1608 ports scanned but not shown below are in state: closed)
Port State Service
22/tcp open ssh
111/tcp open sunrpc
6000/tcp open X11
nmap run completed -- 1 IP address (1 host up) scanned in 3.147 seconds
It reports that there are three ports open on your system.
Now we come to the utility to harden the system so that we don't have to go through and change all of the config files by hand. For this we will use Bastille Linux.
You can read more about what Bastille is on their website before you download it. By following the install instructions, you will be offered a series of questions in regard to the security of your system. Each question will have a brief description regarding the question if you are unclear with some of the context. There are several different security modules that you will need to address such as file permissions, account security, firewalls, etc.
A couple of questions to pay particular to are listed under security modules SecureInetd and ConfigureMiscPam. The first is "Would you like to set a default-deny on TCP Wrappers and xinitd?" and the second is "Would you like to put limits on system resource usage?"
Now that we have Bastille Linux on the system, we'll run nmap again.
#nmap -sF 192.168.1.10
Starting nmap 3.20 ( www.insecure.org/nmap/ ) at 2003-03-19 09:50 PST
Note: Host seems down. If it is really up, but blocking our ping probes, try -P0 nmap run completed -- 1 IP address (0 hosts up) scanned in 12.048 seconds
Now we'll try with the -P0 option like it says.
#nmap -P0 192.168.1.10
Starting nmap 3.20 ( www.insecure.org/nmap/ ) at 2003-03-19 10:00 PST
All 1611 scanned ports on system.foobar.com (192.168.1.10) are: filtered
So now the system is reporting no ports that are open and if you try to ping your system you should be getting no response.
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