Viruses, worms, and Trojan horses have been around a long time. Hacking has been around since computers could talk to each other over a network. Today these threats are more sophisticated than ever, which means that security awareness on the part of network administrators has to be greater.
A firewall with good administration is the best way to protect machines on your internal network from the outside world. There are different types of firewalls, and some are more sophisticated than others. Internet Security and Acceleration Server (ISA Server) is a sophisticated firewall and web cache server, with very useful features such as these:
Application filtering allows the firewall to dynamically open ports for an application type (a streaming media application using the H.323 protocol) and then close those ports after the application is no longer in use.
E-mail filtering looks for unwanted keywords or attachments.
Stateful inspection examines the data crossing the firewall based on protocol and state of connection. It's more secure than basic packet filtering, because it doesn't allow attackers to send packets that fraudulently appear to be part of an existing connection, and it can detect packets with incorrect sequence numbers.
Bandwidth priorities allocate a certain percentage of your network's bandwidth to a particular network resource such as a user, group, or application, and give some of these resources priority over the others when using bandwidth.
This article describes how to install and manage ISA Server on a Windows Server 2003 system. By having Microsoft's most reliable server operating system, firewall, and caching server running together, your network and Web servers will be in good hands!