This is an older post. Please use ufw now. I'll post an update about how to use ufw.
When working with Rackspace Cloud Servers you’re given a vanilla box with nothing on it. This is known to anyone with experience using Rackspace’s Cloud Servers.Which means, when you create a cloud server that hasn’t been spun from your default cloud image, you need to setup a few things. You need to install Apache, MySQL, PHP, etc. All of this depending on how you’re going to use your cloud server. In this article, I’ll be talking to Linux servers instead of Windows (for Windows, contact me).
One thing that many people forget to do is open up the firewall and then finally, save the firewall settings.
The most basic thing you need to do is open up port 80 (the WWW port):
iptables -I INPUT 1 -p tcp –dport 80 -j ACCEPT
For those using SSL, you’ll need to open up port 443:
iptables -I INPUT 1 -p tcp –dport 443 -j ACCEPT
Finally, when you’re done making all your iptable changes, be sure to SAVE what you’ve done:
CentOS and Fedora
# as ROOT
# service iptables save
iptables-save > /etc/iptables.rules
All other Distros
iptables-save > /etc/sysconfig/iptables
Remember, with Rackspace Cloud Servers, you need to install all your software because you’re given by default, an empty server. After you’ve installed all your software, you need to open up your firewall ports (using iptables) and then finally, save what you’ve done.