Featured Article — Windows Professional Protect your system with IP filters—Part 1
If your system is connected directly to the Internet through a leased-line, DSL, cable modem, or other 24x7 connection, preventing intrusion into your system should be high on your list of priorities. Even if it’s your home system and you think no one could possibly be interested in attacking, think again. In your first month of full-time connectivity your system could well have been probed several times and you’d never know it.
A firewall is perhaps the best option for protecting your system, and in an upcoming tip we’ll cover personal firewall software. If you don’t want the cost of such software or your security needs are not as critical, you have another option for protecting the system: IP filters.
IP filters let you specify which TCP/IP traffic comes and goes through a given interface on your computer. You can filter TCP ports, UDP ports, and IP protocols. TCP and UDP are two different protocols used by various network applications over TCP/IP. For example, TCP port 80 is the default port for HTTP traffic (web browsing), UDP port 88 is used for Kerberos authentication traffic, and IP Protocol number 88 is assigned to the Internet Group Management Protocol (IGMP). By restricting the ports and protocols allowed for use on your system you can control the types of traffic coming and going through your computer, potentially avoiding intrusion and denial-of-service attacks. In tomorrow’s tip you’ll learn how to apply IP filters to do just that. |
