These instructions may vary based on the OpenWRT version you use.

Block Google DNS on OpenWRT

1. Open the OpenWRT settings page and navigate to: Network > Firewall >Traffic Rules.
2. Under New forward rule enter DNS as the name, choose source zonelan, destination zone wan and click Add and edit..
3. Enter the following information:
   
   • Name: DNS
   • Restrict to address family: IPv4
   • Protocol: TCP+UDP.
   • Match ICMP type: any
   • Source zone: lan
   • Source MAC address: any
   • Source address: any
   • Source port:
   • Destination zone: wan
   • Destination address: choose Custom and enter 8.8.8.8
   • Action: Reject
   • Extra arguments:
   • 

1. Click Save & Apply.
2. Repeat the same steps for Destination address: 8.8.4.4.
3. Click Save & Apply once more on the Firewall - Traffic Rules page.