DNS leak in pfSense

vinoth · October 12, 2020, 6:38am

I’m using pfSense version 2.4.5-RELEASE-p1. Configured cloudflare DNS. But I noticed so many requests to google DNS from clients. Please help to fix the DNS leak.

LTS_Tom · October 12, 2020, 9:56am

Netgate has a write up here https://docs.netgate.com/pfsense/en/latest/recipes/dns-block-external.html

vinoth · October 12, 2020, 2:21pm

Hi Tom, Thanks for the reply.
I found another doc for the same purpose in Netgate. But this is a NAT rule. So which one do you prefer? https://docs.netgate.com/pfsense/en/latest/recipes/dns-redirect.html

LTS_Tom · October 12, 2020, 5:40pm

Depends on what you want to happen, redirect or fail.

vinoth · October 13, 2020, 3:11am

Thanks Tom. I chose redirect.
Your videos have been so helpful. Keep the good work going. Thanks again.

neogrid · October 13, 2020, 11:34am

Obviously if they are somehow using VPNs and DNS over TLS they can easily circumvent your controls

sdfungi · October 13, 2020, 6:10pm

While making a change at the firewall level can have the effect you are looking for it is only addressing the symptom not the problem. I would recommend only doing this as a stop gap measure until you can correct the issues with the offending systems.