Archive for October, 2015

Save iptables on Shutdown and Restart, and Restore on Boot

Tuesday, October 6th, 2015

Save iptables Rules on Shutdown, Restore on Boot

When your server shutsdown (halts), reboots, or enters runlevel 1, your iptables configuration is automatically wiped and reset.  Packages such as iptables-persistent supposedly help with this problem, but unless you save your rules manually, the rules are never saved automatically when the system reboots. 

I've wanted to truly persist my iptables, so I decided to change their package to always save the iptables rules when the system reboots, halts, or enters runlevel 1 automatically.  The rules are then restored when the system boots to runlevels 2-5.  This means that your iptables configuration will persist forever.  This may not be desired, but if I ban an IP address permanently, I always want it to be banned.

If you'd like to use this modified version of iptables-persistent so that your rules are automatically saved on shutdown, you can install it by running the below commands:

sudo apt-get remove iptables-persistent
sudo dpkg -r iptables-persistent
sudo dpkg --install iptables-persistent_0.5.8_all.deb

Use at your own risk.  If you do something stupid, it will persist until you can clear it!

The above package was tested in Ubuntu 12.04 x86, Ubuntu 12.04 x64, Ubuntu 14.04 x86, Ubuntu 14.04 x64, and Ubuntu 15.04 x64.  Should work on other debian operating systems as well.

Get the Source Code and Modify an Ubuntu Package

Tuesday, October 6th, 2015

Modifiying the Source of a Package and Creating a New Deb Binary

In order to download the source code of an existing package, first install the prerequisites:

sudo apt-get install build-essential debhelper

To get the source code of a package, run the following command:

apt-get source {name_of_package_interested_in}

Make changes to the source using an editor like geany or via terminal through nano.  Edit the changelog file and add a record of your changes to build a new revision number.  After you have made the changes, run the following commands to build the package which should include your changes.

dpkg-source --commit
dpkg-buildpackage -b

The updated package has been built.  To install the package, simply use the below commands:

sudo dpkg --install {name_of_new_deb_file}

To remove the software:

sudo dpkg -r {name_of_package [NOT NAME OF DEB FILE]}

Now you can release it!