Site-wide links

Rochester Institute of Technology logo
Get Safe

Getting Secure


Network Ready

Safety & Security


On Campus

What is a Firewall?

A firewall is a piece of hardware and/or software which functions in a networked environment to prevent some communications forbidden by the security policy. Firewall programs help protect your computer from hackers who might try to delete information from your computer, make it crash, or even steal personal information, such as passwords or credit card numbers. A firewall has the basic task of controlling traffic between different zones of trust. Typical zones of trust include the Internet (a zone with no trust) and an internal network (a zone with higher trust). The ultimate goal is to provide controlled connectivity between zones of differing trust levels through the enforcement of a security policy and connectivity model. RIT Resnet recommends that you use these firewalls to help protect your computer from security vulnerabilities.

Turn On Your Firewall

Not all opperating systems come with built-in firewall software.
Both Windows XP/Vista and OS X come with a built-in firewall.

Windows XP/Vista

  1. Open Windows Firewall.
    • Click Start
    • Click Control Panel
    • Change to Classic View
    • Double-click Windows Firewall
  2. On the General tab, click "On".
  3. Select the Don't allow exceptions check box, and then click OK.

Windows 2000

Windows 2000 do not have built-in firewall software.

If you are running a version of windows other than XP, your computer does not have built-in firewall software. Windows users without built-in firewall protection should visit the Microsoft Security Essentials site for additional information on securing with third-party firewall software.

Additional third-party firewall software may be found at ( or (

Mac OS X

  1. Open System Preferences
    • Select it from the Apple Menu
    • or by clicking it in your Dock
  2. Select Sharing from the Internet & Network preferences section.
  3. Click the Firewall tab and click "Start".
  4. Quit System Preferences.

Linux Users

Depending on your distribution of Linux, your computer may not have built-in firewall software.
For Linux users, Ubuntu is a good choice ( for easy maintenance.
Packet filtering framework inside the Linux 2.4.x and 2.6.x kernel series is often called iptables. Iptables is a generic table structure for the definition of rulesets. Information on iptable can be found at (

Also available is firestarter, it is a nice GUI tool to set a firewall up for you.
A hardware firewall can also be used to protect desktop computers.

<- Back   -----   Next ->