The Internal DNS server will be placed on the Internal network. This protects our Internal DNS server from being compromised by the Internet. The Internal DNS server has information which could be used to map our internal network. This is what our firewall rulebase has to enforce. We will end up using 11 rules for this security policy.
Lets see how.
Before we begin building our rulebase, there is one thing I want to cover, rule order. As you will soon learn, which rules go in what order are critical. Having the same rules, but placing them in a different order, can radically alter how your firewall works. When your firewall receives a packet, it compares it against the first rule, then the second, then the third, etc. When it finds a rule that matches, it stops checking and applies that rule.