DoT with Dnsmasq and Stubby

• This how-to describes the method for setting up DNS over TLS on OpenWrt.
• It relies on Dnsmasq and Stubby for resource efficiency and performance.
• Follow DNS hijacking to intercept DNS traffic or use VPN to protect all traffic.

Install the required packages. Enable DNS encryption.

# Install packages
opkg update
opkg install stubby
 
# Enable DNS encryption
service dnsmasq stop
uci set dhcp.@dnsmasq[0].noresolv="1"
uci set dhcp.@dnsmasq[0].localuse="1"
uci -q delete dhcp.@dnsmasq[0].server
uci -q get stubby.global.listen_address \
| sed -e "s/\s/\n/g;s/@/#/g" \
| while read -r STUBBY_SERV
do uci add_list dhcp.@dnsmasq[0].server="${STUBBY_SERV}"
done
uci commit dhcp
service dnsmasq start

LAN clients should use Dnsmasq as a primary resolver. Dnsmasq forwards DNS queries to Stubby which encrypts DNS traffic.

• https://www.cloudflare.com/ssl/encrypted-sni/
• https://1.1.1.1/help

Collect and analyze the following information.

# Restart services
service log restart; service dnsmasq restart; service stubby restart
 
# Log and status
logread -e dnsmasq; netstat -l -n -p | grep -e dnsmasq
logread -e stubby; netstat -l -n -p | grep -e stubby
 
# Runtime configuration
pgrep -f -a dnsmasq; pgrep -f -a stubby
head -v -n -0 /etc/resolv.* /tmp/resolv.* /tmp/resolv.*/*
 
# Persistent configuration
uci show dhcp; uci show stubby

If you want to manage the settings using web interface.

Navigate to LuCI → Network → DHCP and DNS to configure Dnsmasq.

Stubby is configured with Cloudflare DNS by default. You can change it to Google DNS or any other DoT provider including your own DoT server with Nginx. Use resolvers supporting DNSSEC validation if necessary. Specify several resolvers to improve fault tolerance.

# Configure DoT provider
while uci -q delete stubby.@resolver[0]; do :; done
uci add stubby resolver
uci set stubby.@resolver[-1].address="2001:4860:4860::8888"
uci set stubby.@resolver[-1].tls_auth_name="dns.google"
uci add stubby resolver
uci set stubby.@resolver[-1].address="2001:4860:4860::8844"
uci set stubby.@resolver[-1].tls_auth_name="dns.google"
uci add stubby resolver
uci set stubby.@resolver[-1].address="8.8.8.8"
uci set stubby.@resolver[-1].tls_auth_name="dns.google"
uci add stubby resolver
uci set stubby.@resolver[-1].address="8.8.4.4"
uci set stubby.@resolver[-1].tls_auth_name="dns.google"
uci commit stubby
service stubby restart

Enforce DNSSEC validation if your DNS provider does not support it, or you want to perform the validation yourself. Beware of fault tolerance and performance issues.

# Enforce DNSSEC validation
uci set dhcp.@dnsmasq[0].proxydnssec="1"
uci commit dhcp
service dnsmasq restart
uci set stubby.global.appdata_dir="/tmp/stubby"
uci set stubby.global.dnssec_return_status="1"
uci commit stubby
service stubby restart