It often helps to use concrete examples to help illustrate concepts, so once again we will imagine a hypothetical network in order to understand how we would go about configuring firewall rules for a specific environment. Imagine a network with four subnets: SALES, MARKETING, DEVELOPERS, and a DMZ, and with the following requirements:
All subnets should be allowed to access the internet, subject to the restrictions outlined as follows:
- SALES should not be able to talk to MARKETING and DEVELOPERS; MARKETING should not be able to talk to SALES and DEVELOPERS; DEVELOPERS should not be able to talk to SALES and MARKETING.
- SALES, MARKETING and DEVELOPERS should be able to talk to the DMZ, but the DMZ should not be able to talk to any local subnets (other than DMZ).
- SALES and MARKETING share a printer that is on the MARKETING subnet, so SALES should have access to...
