The need for a firewall is obvious to most site owners, yet many fail to implement adequate firewall protection. Auto-check your Web site. This process can be and is normally contracted to an outside agency, which might be costly. Keep the system simple. Minimise the number of services running on the systems by turning off the options you don't need.
Most operating systems are insecure in the default configurations.
Keep the system simple by shutting down all services that aren't required. Stay current on upgrades, updates, vendor advisories, and security bulletins. When using software, even one version old can open the door to a DoS attack. Stay vigilant through testing and monitoring. Installation of IDS systems around hardened firewalls combined with proper CPU, memory, and bandwidth monitoring will provide the information that is the key to success.