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What is a firewall and how does it work? A firewall is a piece of software that sits between two networks that acts like a security guard that will allow certain types of data in and keep other certain types out. For example, it can allow traffic from the World Wide Web in, but not data from AOL Instant Messenger. This is useful for a couple of reasons. If you were a network for a school and didn't want your students downloading songs from Napster while they're supposed to be researching with the web, you can block Napster traffic out. More importantly perhaps, a firewall can keep hackers out of the computers on your network. The Asante FriendlyNET Series Routers have two types of firewall protection: Network Address Translation (NAT) and TCP/UDP port blocking. Network Address Translation is the process whereby the router assumes the IP address that your ISP provides you. It then splits, or translates that IP address into up to 253 different private IP addresses. Each computer connected to the router can then access the Internet as if it was connected directly to the Internet. However, the 253 private addresses cannot be addressed from the outside because they are not "real". This means that the addresses the router gives each computer are for internal use in your Local Area Network and are not accessible from the outside. Thus, the only piece of hardware that a hacker would be able to access from the outside is the router itself. The Asante FriendlyNET Series Routers are nearly impossible to hack and have been designed from the ground up for security. To understand TCP/UDP port blocking, one must first understand what a TCP/UDP port is. Every type of traffic that is transmitted has a number that identifies what kind of data it is. For instance if the data being sent is type 80, then it is World Wide Web data. If it is type 21, it is FTP, 6699 and 7000 are Napster, and 4000 is ICQ. These numbers are TCP/UDP ports. TCP/UDP port numbers are located in the IP Address. For example, if you wanted to talk to the IP address 192.168.123.254 and get WWW type data, your computer would send the address 192.168.123.254:80. The :80 part is the port number. There are 65,535 TCP/UDP port numbers, some of which are currently unassigned. TCP/UDP port blocking can disallow certain types of data from coming into your network. It is very useful for restricting what types of activities can be performed on a network. Not only can it prevent employees or students from playing games, chatting, etc., but it can also be used to stop hacker attacks before they start by blocking traffic to certain vulnerable ports. For more on configuring TCP/UDP ports on your FriendlyNET 3004 Series router, please see the Advanced Features items listed under "Configuring the firewall" in the Advanced Page. |
