A quick way to secure a Linux system
by Paul Christensen - Tuesday, 8 April 2003.
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

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

Starting nmap 3.20 ( www.insecure.org/nmap/ ) at 2003-03-19 10:00 PST

All 1611 scanned ports on system.foobar.com ( 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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