| Firewall Design |
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There are different implementations of firewalls. We present some well known, easy to implement, reliable firewalls. The most simple setup is presented in Diagram 1. Diagram 1 Starting from typical firewall a version with 2 LANS can be implemented. Distinct two LANs will be on different subnets, and will not see each other. This setup can also be implemented with a managed switch and virtual LANs. Typical firewall with 2 lans is presented in Diagram 2.  Diagram 2 If we have a Web Server, Mail server, Database Server and we want to separete is from internal LAN, we can use DMZ setup (DMZ = Demilitarized Zone). Servers located on DMZ will not be seen from LAN and viceversa. (will be on different subnets).  Diagram 3 Another interesting firewall setup is to achieve High Availability. That means we will use two Internet lines, with two firewalls. If one firewall or Internet connection fail, Internet conectivity will not be lost, the traffic will go trough firewall which is up. High Availability is implemented in Diagram 4.  Diagram 4 |
