Linux is an alternative operating system for computers. It's one of the most well-known example for free softwares and open source codes. It can be freely modified, used, and redistributed by anyone.
In the interest of the system's security the most important and the available files are separated. Linux can be used by more users. This would make the computer more vulnerable but it doesn't. The users don't have access to the root's applications so we can't modify them accidentally. The viruses can't access to the system settings because the configure files are in a /etc directory and all this together gives the stability of the Linux.
Security-Enhanced Linux (SELinux) is an extra security service. We can define in one configuration that who has access to which applications and server and network procedures. This makes our network more protected.
SELinux implements security policies with the use of Linux Security Modules. LSM is a framework that lets Linux kernel to support security models. It has a lot of features for example the interfaces are well-defined, the policy is very flexible and it support for policy changes. The controls over the file systems, directories, files, messages and network interfaces are strong.
SELinux has become available for simple users with in a package with Red Hat Enterprise Linux version 4 and all future releases as well. It can be installed not only with Red Hat but with Fedora, Hardened Gentoo and Yellow Dog as well.
Firewalls are necessary for computers if we have internet on it. There are different kinds of methods how the firewalls work and check the incoming information. At the same time the firewalls let the outgoing ports open. It gives security for our computer and protect it from the system mistakes as well. For personal computers it can be enough and useful but for networks maybe not.
Linux uses iptables filter to give stronger protection and security. It's a software in basic Linux packages. We can exatly determine that how we would like to check the incoming traffic with this program. We can define the criterias for each ports, services and we can define our own strict rules for our incoming traffic.
For network level's security there are several distributions for firewalls. IPCop is one of them. It's only for security. We need a computer on which IPCop is running and there are some basic activities like framework, connection to network and routing. Linux distributions like SUSE or Fedora use to have graphical desktop, text editor and more softwares but on IPCop there are only these basic activities and the previously mentioned very important iptables. It's our firewall between our network and the internet so we don't work on it.
www.infosecuritylab.com
