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docs:guide-user:services:dns:dot_dnsmasq_stubby

DNS over TLS via Dnsmasq and Stubby

Introduction

  • This guide describes how to configure OpenWrt to protect your DNS traffic.
  • It utilizes DNS over TLS to provide DNS encryption.
  • DNS encryption is limited to DNS traffic, use VPN to protect all traffic.

Goals

  • Encrypt your DNS traffic improving security and privacy.
    • Prevent DNS leak and DNS hijacking.
  • Bypass regional restrictions using public DNS providers.
    • Escape DNS-based content filters and internet censorship.

Instructions

This method utilizes DoT via Dnsmasq and Stubby and maintains a balance between resource efficiency and performance.

Enable split DNS mode to encrypt LAN client DNS traffic assuming that local system traffic does not involve private data.

Use Stubby to encrypt DNS traffic. Configure Dnsmasq to forward DNS queries to Stubby. Enforce DNS encryption for LAN clients to avoid DNS leak.

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

See also: DNS hijacking, Random generator

Testing

Verify that domain name resolution works.

nslookup openwrt.org localhost

Check your DNS provider. Make sure there is no DNS leak.

Test DNSSEC validation.

Troubleshooting

Collect and analyze the following information.

# Restart the 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
 
# Persistent configuration
uci show dhcp; uci show stubby

Extras

DoT provider

Stubby uses Cloudflare DNS by default. You can change it to another DoT provider. Make sure selected provider supports DNSSEC validation if required. Specify several servers to improve fault tolerance.

# Configure DoT provider
while uci -q delete stubby.@resolver[0]; do :; done
uci set stubby.dns6a="resolver"
uci set stubby.dns6a.address="2001:4860:4860::8888"
uci set stubby.dns6a.tls_auth_name="dns.google"
uci set stubby.dns6b="resolver"
uci set stubby.dns6b.address="2001:4860:4860::8844"
uci set stubby.dns6b.tls_auth_name="dns.google"
uci set stubby.dnsa="resolver"
uci set stubby.dnsa.address="8.8.8.8"
uci set stubby.dnsa.tls_auth_name="dns.google"
uci set stubby.dnsb="resolver"
uci set stubby.dnsb.address="8.8.4.4"
uci set stubby.dnsb.tls_auth_name="dns.google"
uci commit stubby
service stubby restart

DNSSEC validation

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

Local system DNS via Dnsmasq

Enforce DNS encryption for local system. Override DNS encryption for NTP provider to avoid deadlock state if system time is not synchronized. Beware of fault tolerance issues.

# Enforce DNS encryption for local system
uci set dhcp.@dnsmasq[0].localuse="1"
 
# Fetch DNS provider
source /lib/functions/network.sh
network_find_wan NET_IF
network_find_wan6 NET_IF6
network_get_dnsserver NET_DNS "${NET_IF}"
network_get_dnsserver NET_DNS6 "${NET_IF6}"
 
# Override DNS encryption for NTP provider
uci get system.ntp.server \
| sed -e "s/\s/\n/g" \
| sed -e "s/^[0-9]*\.//" \
| sort -u \
| while read NTP_DOMAIN
do
uci add_list dhcp.@dnsmasq[0].server="/${NTP_DOMAIN}/${NET_DNS%% *}"
uci add_list dhcp.@dnsmasq[0].server="/${NTP_DOMAIN}/${NET_DNS6%% *}"
done
uci commit dhcp
service dnsmasq restart
docs/guide-user/services/dns/dot_dnsmasq_stubby.txt · Last modified: 2019/05/26 17:01 by vgaetera