| 1.4 |  | Security Products and Solutions |
| 1.4.3 |  | Firewalls |

| The most well-known security device is the firewall. By conventional definition, a firewall is a partition made of fireproof material designed to prevent the spread of fire from one part of a building to another. A firewall can also be used to isolate one compartment from another. When applying the term firewall to a computer network, a firewall is a system or group of systems that enforces an access control policy between two or more networks .

There are many vendors of firewalls, however all firewalls fall within three classes:

- Dedicated firewalls
- Server firewalls
- Personal firewalls

Cisco provides a full lineup of firewall devices . This course will help students design, install, and configure firewalls using IOS Firewall routers and PIX firewalls.

Dedicated firewalls
There are many dedicated hardware appliance-based firewalls available to secure a network. Cisco provides an integrated IOS Firewall and a dedicated Private Internet Exchange (PIX) Firewall. The IOS Firewall feature set can be installed and configured in perimeter routers. It adds features such as stateful, application-based filtering, dynamic per-user authentication and authorization, defense against network attacks, Java blocking, and real-time alerts. The PIX Security Appliance is a dedicated hardware/software security solution/appliance that provides packet filtering and proxy server technologies. Other dedicated firewall vendors include Netscreen, Nokia, and Nortel Networks.

Server based firewalls
A server-based security solution runs on a network operating system (NOS) such as UNIX, NT or Win2K, or Novell. It is generally an all-in-one solution that combines a firewall, access control, and virtual private networking features into one package. Examples of a server-based security solution include Microsoft ISA Server, Novell BorderManager, and Check Point Firewall-1.

Remember that dedicated firewalls are specialized computers as well, but they run only a single firewall application or operating system, whereas server based firewalls run on top of a general purpose OS. Server based firewalls tend to be less secure than dedicated firewall because of security weaknesses of the general purpose OS. Server based firewalls typically do not perform as well in high bandwidth networks compared to dedicated firewalls .

Personal firewalls
Personal computers connected to the Internet through a dialup connection, DSL, or cable modems are as vulnerable as corporate networks . Personal firewalls reside on the user’s PC and attempt to prevent these attacks. Personal firewalls are not designed for LAN implementations, and they may prevent network access if installed with other networking clients, services, protocols, or adapters. Some personal firewall software vendors include McAfee, Symantec, and Zone Labs.

| Web Links Cisco http://www.cisco.com/warp/public/ cc/pd/iosw/ioft/iofwft/ http://www.cisco.com/warp/public/
cc/pd/fw/sqfw500/

Microsoft
http://www.microsoft.com/isaserver/

Firewall Certifications
http://www.icsalabs.com