See Part I of this article

This is Part II of Setup Ubuntu Server in the Cloud series.

4. Install and configure a firewall
Having a firewall in your system is mandatory. Configuring it correctly is even more important. I use 'iptables' for that matter and here is the command to install it, and then check its configuration which, at this time is empty:

dambrosio@XXXCNN4730:~$ sudo apt-get install iptables
dambrosio@XXXCNN4730:~$ sudo iptables -L

I just bought a server in the Cloud to run my development tools (i.e. SVN, JIRA, MySQL etc.). It is a 8.04 Ubuntu server with root access. So I need this server to work the way I want it, so here are the steps I took to prepare it:

1. Change the .bashrc file
I am so used to typing 'll' in the command line as alias for 'ls -lsa' that the first thing I changed was the .bashrc file to have the standard aliases enabled.

Type:

root@XXXCNN4730:/# vi ~/.bashrc

I just installed Ubuntu 9.10 (the Karmic Koala, as they call it) at my home Desktop. First thing I tried was to check whether my ssh daemon was running, and it wasn't. I did have the ssh client but not the scripts to start the server, but no panic. It is quite fast to fix this. Jut open a terminal window and type the following to install OpenSSH.

sudo apt-get install openssh-server openssh-client

I did not need the client as I had it installed already. Here is the result from the command above:

First things first: SSH is (very) simply put a secure way to access the command shell from remote servers, because all the communication is encrypted, even the password that you use to connect.
The ssh protocol also allows one to establish a tunnel for communication between two machines, which is also a secure mean of sending information (because is encrypted) or circumventing firewall restrictions in your environment.