Go back to the archive

Control your network traffic - One of the best ways to protect your information systems is to control the network traffic coming into and leaving them. Many organizations will use a perimeter security device, such as a firewall, that sits between the Internet and the organization's internal network. The firewall operates as a "network traffic cop" to control what traffic comes into your organization and what traffic leaves your organization. Controlling network traffic is such an important security task that many operating systems include software-based firewalls that can control the traffic coming into or leaving the system itself. The generally accepted best practice is to deny all network traffic and only allow what you know needs to come into your network. For example, if you have a web server that you want anyone to be able to see you will most likely want to allow HTTP and HTTPS traffic from the Internet to reach that web server but there's no reason to allow all the other network traffic floating through the Internet to reach your web server. Restricting and filtering network traffic is a very important aspect of maintaining a secure system - especially a system that's connected to the Internet in any way.

The term "firewall" is loosely applied to any device or software package that controls network traffic. Vendors such as Cisco, Checkpoint, and others produces appliance based firewalls capable of handling very large volumes of traffic. Linksys, Netgear, and others produce products for small office or home use. Microsoft, Symantec, McAfee, and others produce software-based firewalls that can be loaded onto individual systems to control network traffic for that specific system.

External Links:

About firewalls

Windows firewall

Iptables

Understanding Windows firewall

 

© 2009 The Center for Infrastructure Assurance and Security