Firewall

Security is essential for day to day operations of every business and individual. A security breach can lead to wide range of problems, from limited downtime (out of service) to more serious ones like data loss. That is why implementing the right security policy from the start is the recommendation of most experts. All the components to prevent and recover safely from a potential breach should be planned and deployed carefully beforehand - backup and recovery strategy, monitoring, access controll, firewalls and so on.

Firewalls prevent and limit unwanted traffic. Having a properly setup firewall is 50 to 70 percent of your infrastructure security. The rest is encryption, access controll, backup and monitoring. The firewall is meant to allow access and traffic from trusted sources and to block unauthorized parties.

There are different ways to setup and keep in sync a firewall - physical hardware manufactured by big network equipment companies, GNU/Linux and *BSD software based firewalls, cloud firewalls and dedicated software services companies for traffic management. The actual firewall policy can also vary - per host or network segment, by destination port, per source and destination IP address and so on. What and how should be implemented highly depends on the scenario, the software and protocols used. The common case for a firewall is usually straight forward, but often in real-life situations the requirements often mandate a bit more.