When you are dealing with a machine security, the very first things that comes to your mind is setting up a mechanism so that only authorized personnel can access your machine. Setting up username/password, SSH based authentication are few ways to implement access control. However, a most useful tool for any administrator is to setup firewall on the machine. UFW i.e. uncomplicated firewall is a firewall implementation available on linux distros such as Ubuntu and CentOS.
What is a Firewall?
In simple terms, a firewall is a system that filters out incoming as well as outgoing traffic based on set rules. A system administrator can set up rules to allow incoming traffic only on a certain port such as 80 (HTTP) and 443 (HTTPS). In such a case, this server won’t be accessible over SSH, which uses port 22. Or System administrator can set up a rule to allow incoming traffic only from certain IP addresses. And the list goes on. A firewall could be a system application such as iptables on Linux or a hardware solution (e.g. Linksys router).
What is ufw?
ufw stands for “uncomplicated firewall”. It is simply a command line interface for iptables available on Linux systems.
Linux provides a packet filtering system called “netfilter”. iptables is a suite of commands used to manipulate the netfilter. However, understanding iptables has turned out to be a very difficult task and hence several frontends were developed to make firewall maintenance easy for system administrators. ufw is such a frontend for iptables.
ufw is readily available on Ubuntu systems. Its equivalent application on CentOS, Fedora, and RedHat systems is “FirewallD”. However, if you want you can install ufw on CentOS as well. [link]
If you want to see how ufw provides an easy interface for several common operations, read this link.
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Ubuntu, CentOS, Fedora, RedHat Linux, Firewall, WAF, ADC