Situation:
You have a LinkSys DSL router and it contains a firewall. You want to know whether Norton Internet Security (NIS) and Norton Personal Firewall (NPF) conflict with that firewall.

Solution:
The firewall in the LinkSys routers is called a Network Address Translation (NAT) firewall. This firewall filters IP addresses at the router, which is before communications from the Internet or other external network reach the computers on your internal network. So, this firewall does not conflict with NIS or NPF.

More information
NAT firewalls are simple firewalls that act as a proxy, which prevents or discourages direct access to the computers that are connected to the router. NAT masks the IP addresses of the computers on the internal network so that they are not visible to computers on the Internet or to other external networks. Communications from the Internet or other network can reach the computers on your internal network only if they use an IP address that you have configured the LinkSys firewall to accept.

While the NAT firewall discourages access, it does not totally block access. Incoming communications from any permitted IP address can still reach computers on the internal network, and communications from the computers on the internal network can still send communications over the Internet.

NIS and NPF regulate access to the computers on the internal network at the time that those communications reach those computers, which is after the communications have been filtered through the NAT router. NIS and NPF, in addition to being able to filter communications from specific IP addresses, can regulate access to your computer based on which program attempts the communication, the port that the program attempts to use, the nature of the originating Web site, the communication protocols in use, and similar features of the incoming communications.

Document ID: 2003011309552336
Last Modified: 09/23/2003
Date Created: 01/13/2003
Product(s): Norton Internet Security 2003 6.0, Norton Internet Security 2004 7.0, Norton Internet Security Professional 2003, Norton Internet Security Professional 2004 7.0, Norton Personal Firewall 2003 6.0, Norton Personal Firewall 2004 7.0