IPTables for DNS redirection

[Shrmn]

Hi guys,

I'm trying to set up a set of iptables rules to redirect Google Public DNS Servers to another set of DNS servers as the Chromecast has Google's IP Addresses hardcoded in the device.

I have the Chromecast's IP Address static on 192.168.1.123 and am attempting to reroute all DNS requests originating from the Chromecast to 8.8.8.8 and 8.8.4.4 to end up to a DNS server 1.2.3.4 (for privacy's sake) instead. I have them set up under jffs firewall-start but they don't seem to work:

iptables -I PREROUTING -t nat -p udp -s 192.168.1.123 -d 8.8.8.8 --dport 53 -j DNAT --to-destination 1.2.3.4
iptables -I PREROUTING -t nat -p udp -s 192.168.1.123 -d 8.8.4.4 --dport 53 -j DNAT --to-destination 1.2.3.4

SSH-ing directly into the router and keying in the above line gives me this:

iptables v1.4.14: multiple -p flags not allowed

I've tried --protocol and uppercased UDP as well and they still produce the same message. I'm lost.


Would anyone please help me out?

Cheers!

 

[RMerlin]

Use DNSFilter, on the Chromecast's MAC address.

 

[Shrmn]

Use DNSFilter, on the Chromecast's MAC address.

Sorry, I'm unsure on how I would go about using such a tool. The dnsfilter command via SSH tells me its not found and I can't seem to find such an option on the Web GUI (I'm using your latest build on an AC68U)

 

[ColinTaylor]

Go to Parental control > DNS Filtering

 

[RMerlin]

And also read the documentation that came with the firmware.