Technology Facts

These days many PCs and Laptops like EEE PC come with pre-installed Linux Operating system.  Many people just use these Linux based computers for browsing the web, sending  & receiving email and for messenger based chats. Most of these computers are single user, stand alone computers.  Linux based computer can be made more secure defining who can access it and who cannot. This basic security hack works even when you are not behind a firewall.

To make your Linux based computers more secure all you have to do is to edit the files which allow and deny the access to the local computer from remote computer. These files are /etc/hosts.allow and /etc/hosts.deny. In /etc/hosts.allow you can define which host i.e.  computer has permission to access which service on the local machine. In /etc/host.deny you can define which services on the local host (machine) are denied to which remote host. This is a very basic form of security . By editing just these two files and by adding the lines as shown below you can make you Linux box more secure. Just follow the following procedure to make your standalone Linux box more secure.

1. Login as a root user.
2. Edit file /etc/hosts.allow and add following line to it:- ALL:127.0.0.1
3. Now save /etc/hosts.allow and open /etc/hosts.deny for editing.
4. Add following line to /etc/hosts.deny :- ALL:ALL

The first line ALL:127.0.0.1  in /etc/hosts.allow allows local host a total access to all the services on localhost, so you yourself can work on this machine. Remember 127.0.0.7 is the loopback address of the local host.  The second line ALL:ALL in /etc/hosts.deny denies access to all other machines which have not been given permission for access in /etc/hosts.allow.