The personal firewall
By Adesh Rampat
With the increasing use of always-connected cable modems and DSL, the home or small business PC user needs to be aware of security. This tip explains what a firewall does and how to choose one. Here at searchSecurity we are always looking for more security tips, so submit your own
A few years ago a user surfing the Internet at home had no worries about someone on the other end spoofing around and accessing data on the hard drive, or even worse, deleting data. Nowadays users surfing the Internet without a personal firewall are exposing themselves to serious disaster. Securing the home personal computer from Internet hackers has become just as important as securing the corporate workstation.
The home user can be protected from Internet hackers through the use of a personal firewall. There are basically two types of personal firewalls:
- Packet filters block incoming traffic to well-known TCP and UDP ports, while enabling outgoing traffic. This is also known as an application-based firewall.
- Then there is the other type of firewall that performs IP level monitoring; that is, reading data contained in the TCP/IP header for approved protocols and suspicious packet contents.
So what should a user look for when selecting a personal firewall? It all depends on the user's needs. If the user wants to identify the source of a hacker, then a firewall that performs IP level monitoring can be used. If on the other hand the user is interested in monitoring inbound traffic, rather that tracing a hacker, then the application-based firewall should be used.
Although a personal firewall helps in protecting the user against attacks, the following are guidelines that can apply even if there is no firewall installed:
- Have the latest service packs for the Internet browser installed on the PC.
- Never run any executables or scripts via e-mail unless the user is sure that the e-mail sent is protected. Have the latest service updates for e-mail client software.
- Set the file permissions of "normal.dot" in Microsoft Word to read only to prevent viruses or Trojans from affecting the Word setup.
- When surfing the Internet, file sharing should be disabled.
Things to look for in a personal firewall:
- A firewall should be effective in intrusion detection.
- A firewall should provide an activity log to alert the user of attempted intrusions.
- A firewall should be effective in blocking attacks and discovering the identity of the attacker.
- Most importantly, register with the firewall manufacturer to download regular updates or fixes.
- Since attacks occur especially when the user has file sharing enabled, a personal firewall should offer the option of disabling file sharing.
About the author
Adesh Rampat has 10 years of experience with network and IT administration. He is a member of the Association of Internet Professionals, the Institute for Network Professionals and the International Webmasters' Association. He has also lectured extensively on a variety of topics.
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Building Internet Firewalls, Second Edition
Author : Elizabeth D. Zwicky, Simon Cooper and D. Brent Chapman
Publisher : O'Reilly & Associates
Published : July 2000
Like the bestselling and highly respected first edition, Building Internet Firewalls, Second Edition, is a practical and detailed step-by-step guide to designing and installing firewalls and configuring Internet services to work with a firewall.
This was first published in July 2001