OpenWRT, fwbuilder and wallwatcher

Installing the right packages

To get the fwbuilder generated scripts up and running on a OpenWrt powered device, you need to install a few packages. Those packages are found in de standard repository of white russian. The packages you need to install from that repository are ip_2.6.11-050330-1_mipsel.ipk, iptables-mod-extra_1.3.3-2_mipsel.ipk and iptables-utils_1.3.3-2_mipsel.ipk

Editing /etc/firewall.user

I am using a SquashFS version of OpenWrt. This means that the real filesystem is readonly and that all files are available with symbolic links on a writeable JFFS filesystem. What we now need to do is to delete the symbolic link and copy the real file in place of the symbolic link in the /etc directory.

Now we need to add the following code to the firewall.user file.

insmod ipt_LOG
insmod ipt_limit

if [not -f /usr/sbin/firewallscript.fw ] ; then
{orginal script}
else /usr/sbin/firewallscript.fw

Now you have to place your firewall script in the /usr/sbin directory (or place it at a location of your choice, but you will have to edit the code above to match your location).

Instead of adding the two insmod lines in the firewall.user file, you can also edit the file /etc/modules. You can just edit the file like the example below.


Remote syslog with wallwatcher

Now we have to set up remote syslog, so we can log the output of your firewall script with wallwatcher. Remember to put some rules in fwbuilder on logging, otherwise we will never log a thing. You need to set up OpenWrt to use a remote syslog server. You need to replace the with the ip-address of the system that will be running wallwatcher.

nvram set
nvram commit

The only thing you have to do next is to set up wallwatcher router tab

Change Startup order

With the RC5 release of OpenWrt all was working just fine, but when I started to use the RC6 version of OpenWrt I discovered that the firewall script was not executed after a reboot of the router. The problem seemed to be that the /etc/init.d/S35Firewall is executed before /etc/init.d/S40Network. So, When I renamed /etc/init.d/S35Firewall in /etc/init.d/S45Firewall and rebooted the router, the firewall script was executed and all worked just fine.