Tuesday, November 13, 2007

SCO Guilty of Lying About Unix Code in Linux

SCO Guilty of Lying About Unix Code in Linux

In Germany SCO is found guilty of lying about stolen Unix code being in Linux.

In the United States, SCO's Linux/Unix litigation has been stalled out while the company's bankruptcy trial is being dealt with. In Germany, however, several court cases have found SCO Group GmbH, SCO's Germany branch, guilty of lying about Linux containing stolen Unix code.

Sunday, October 07, 2007

How I setup a firewall using IPTABLES

There are many software firewalls available for Linux but since Linux usually comes with a firewall called IPTABLES, I decided to implement it by hand instead of using any GUI tools.

I started by searching online and found a few good tutorials and ready made scripts. There are also many script generators available, however, I recommend that you understand how IPTABLES work.

create a BASH script (here I name it iptables.rules and store it in /etc):

# flush all chains
iptables -F
# set the default policy for each of the pre-defined chains
iptables -P INPUT DROP
iptables -P FORWARD DROP
# allow establishment of connections initialised by my outgoing packets
iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
# drop everything else
iptables -A INPUT -i eth0 -p udp -j DROP
iptables -A INPUT -i eth0 -p tcp -m tcp --syn -j DROP
# accept anything on localhost
iptables -A INPUT -i lo -j ACCEPT

make sure the script file is given execute file attributes:
# chmod +x iptables.rules

now when this script is executed the firewall is on:

# sh uptables.rules

But were are not done yet. If the system is rebooted the script has to be run again manually. So, it's important to launch the script automatically every time the system is booted.

To do this , an init.d script needs to be created (here I named it firewall and put it in /etc/init.d/):

if [[ $1 == start ]] ; then
sudo /etc/iptables.rules
sudo iptables -F

again I added the execute file attribute to this file

Finally I linked the scripts to the boot up process:

# update-rc.d firewall start 20 2 3 4 5 . stop 99 0 1 6 .

Have a safe surf

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Saturday, October 06, 2007

The New York Times praises Linux

The New York Times has a very interesting and positive article on Linux.

read it here

Thursday, October 04, 2007

System hardware information

There are several tools available in Window managers like KDE and Gnome that provide information about the hardware. However on servers, there are usually no Window managers loaded therefore the command line interface must be used to query the hardware information. lspci and procinfo are useful tools that can be use.
You can also install sysinfo to provide all the info together.

Saturday, September 29, 2007

how to add user to group

#usermod -G -a group_name user1

or edit /etc/group

SSH tricks

Polishlinux.org has a very nice article about using SSH

read it here

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How to update Ubuntu by CLI

#sudo aptitude -y update && sudo aptitude -y upgrade && sudo aptitude -y dist-upgrade && sudo aptitude autoclean

To schedule automatically executing the command string but the string in a cron job:

#sudo crontab -e