A lot of our customers have asked for firewalls, and since this is a common theme, i decided that I would help them out. Of course it can be a mission to learn how to make your own and what to do or not do, and some of the pre-made ones can be confusing.
So i decided to simplify it a little for you all by writing a firewall script. I originally took a script made by somebody else, then totally modified it to suit myself, then modified it again to suit any machine. You *should* be able to literally drop this in place on any server and have it *just work*.
All you need to do is edit the top couple of lines to set what ports you want open or closed. edit the other options (ie ssh port etc). Full instructions as follows
wget http://b.ri.mu/files/firewall nano firewall # ctrl+x to exit when finished editing chmod +x firewall ./firewall
If you are still able to connect to your VPS in all the usual ways then you can add that into your init scripts. To check what ports you have open and want the outside world to connect to you can use
netstat -pant |grep LISTEN
If you are unable to login then you may need to log into the console of your VPS at https://rimuhosting.com/cp/vps/console.jsp
Adding it into the init scripts
cp firewall /etc/init.d/firewall
Debian Based (debian.ubuntu etc)
update-rc.d firewall defaults
chkconfig --add firewall