DoT with Unbound

This article relies on the following:

Introduction

  • This how-to describes the method for setting up DNS over TLS on OpenWrt.
  • It relies on Unbound for performance and fault tolerance.
  • Follow DNS hijacking to intercept DNS traffic or 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.

Command-line interface

Disable Dnsmasq DNS role or remove it completely optionally replacing its DHCP role with odhcpd.

Install the packages and enable DNS encryption. 

# Install packages
opkg update
opkg install unbound-daemon ca-bundle
 
# Enable DNS encryption
while uci -q delete unbound.@zone[0]; do :; done
uci set unbound.forward="zone"
uci set unbound.forward.enabled="1"
uci set unbound.forward.fallback="0"
uci set unbound.forward.zone_type="forward_zone"
uci set unbound.forward.tls_upstream="1"
uci set unbound.forward.tls_index="dns.google"
uci add_list unbound.forward.zone_name="."
uci add_list unbound.forward.server="2001:4860:4860::8888"
uci add_list unbound.forward.server="2001:4860:4860::8844"
uci add_list unbound.forward.server="8.8.8.8"
uci add_list unbound.forward.server="8.8.4.4"
uci commit unbound
/etc/init.d/unbound restart

LAN clients and local system should use Unbound as a primary resolver assuming that Dnsmasq is disabled.

Testing

Use nslookup to 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 services
/etc/init.d/log restart; /etc/init.d/unbound restart
 
# Log and status
logread -e unbound; netstat -l -n -p | grep -e unbound
 
# Runtime configuration
pgrep -f -a unbound
head -v -n -0 /etc/resolv.* /tmp/resolv.* /tmp/resolv.*/*
 
# Persistent configuration
uci show unbound

Extras

Web interface

Install the necessary packages if you want to manage the settings using web interface. 

# Install packages
opkg update
opkg install luci-app-unbound
/etc/init.d/rpcd restart

Navigate to LuCI → Services → Recursive DNS to configure Unbound.

DoT provider

Unbound is configured with Google DNS. You can change it to Cloudflare DNS or any other DoT provider including your own DoT server with Nginx. Make sure the resolvers support DNSSEC validation if required. Specify several resolvers to improve fault tolerance. 

# Configure DoT provider
uci set unbound.forward.tls_index="cloudflare-dns.com"
uci -q delete unbound.forward.server
uci add_list unbound.forward.server="2606:4700:4700::1111"
uci add_list unbound.forward.server="2606:4700:4700::1001"
uci add_list unbound.forward.server="1.1.1.1"
uci add_list unbound.forward.server="1.0.0.1"
uci commit unbound
/etc/init.d/unbound restart

DNSSEC validation

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 unbound.@unbound[0].validator="1"
uci commit unbound
/etc/init.d/unbound restart
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  • Last modified: 2021/05/06 08:49
  • by vgaetera