Enabling DoH/DoT in browsers

Firefox

Enable DoH:

  • Go to Settings → Network Settings → Enable DNS-over-HTTPS.

  • Choose a provider (Cloudflare, NextDNS).

Force DoH (about:config):

network.trr.mode = 3  # Force DoH
network.trr.uri = "https://cloudflare-dns.com/dns-query"

Chrome/Edge

Enable DoH:

  • Navigate to chrome://flags/#dns-over-https → Enable.

  • Select a provider (Google, Cloudflare).

System-Wide DoT (Linux/macOS)

Configure systemd-resolved:

sudo nano /etc/systemd/resolved.conf

Add (ini):

[Resolve]
DNS=1.1.1.1#cloudflare-dns.com
DNSOverTLS=yes

Restart:

sudo systemctl restart systemd-resolved

Verify DoH/DoT

Check DNS encryption:

 # Linux
 sudo tcpdump -i eth0 -n port 53  # Should show NO plaintext DNS
 # Windows
 Wireshark filter: `dns && !(tls || http)`

Test with Cloudflare’s checker:

curl -s https://1.1.1.1/help | grep "DNS over HTTPS"