Routing between subnets on different switches connected by a router/firewall

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http://serverfault.com – I have 2 networks that I'd like to connect with a router/firewall to filter traffic between the two. One network is on a public subnet, let's say and the other network is on a private subnet The are connected via a router which has three ethernet ports, one connected to the internet, the other two connected to the public and private subnets and are on their own VLANS. How do I make the private subnet visible to the public network? Here's the network diagram: Router1 >eth0 --- Connected to Internet Router1 >eth1 --- Connected to VLAN 64 Subne (HowTos)