How can I use different DNS for computers behind DD-WRT?

Question

I do the IT work for the church I attend. There are about 30 computers behind a router flashed with DD-WRT. I have it set to use the OpenDNS service mainly for content filtering. Adult content needs to be blocked for all computers, but only as select few need sites like Facebook, Youtube, etc... blocked.

How can I set up DD-WRT to basically segment the computers? We have 5 external IPs, so if I could get DD-WRT to send traffic over 1 IP for most, and another IP for the rest, I could easily set up OpenDNS to block what is appropriate for each network.

Answer 1

The term in this case is "One-to-one NAT". This dd-wrt.com article describes it as :

One-to-one NAT (aka Static NAT) is a way to make systems behind a firewall and configured with private IP addresses appear to have public IP addresses.

The above article describes with examples how to setup new public static IP on dd-wrt WAN interface, then use firewall rules to NAT these external IPs to your internal IPs. This will involve making static all internal addresses.

Some user-cases can be found in thread multiple external IP addresses.