DNSCrypt with Dnsmasq and dnscrypt-proxy2
Introduction
- This how-to describes the method for setting up DNSCrypt on OpenWrt.
- It relies on Dnsmasq and dnscrypt-proxy2 that supports DNSCrypt v2, DNS over HTTPS and Anonymized DNSCrypt.
- 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 leaks and DNS hijacking.
- Bypass regional restrictions using public DNS providers.
- Escape DNS-based content filters and internet censorship.
Command-line instructions
Install the required packages. Enable DNS encryption.
# Install packages opkg update opkg install dnscrypt-proxy2 # Enable DNS encryption service dnsmasq stop uci set dhcp.@dnsmasq[0].noresolv="1" uci set dhcp.@dnsmasq[0].localuse="1" uci set dhcp.@dnsmasq[0].cachesize='0' uci -q delete dhcp.@dnsmasq[0].server uci add_list dhcp.@dnsmasq[0].server="127.0.0.53" sed -i "32 s/.*/server_names = ['google', 'cloudflare']/" /etc/dnscrypt-proxy2/*.toml uci commit dhcp service dnsmasq start service dnscrypt-proxy restart # Ensure, that the NTP server can work without DNS uci del system.ntp.server uci add_list system.ntp.server='194.177.4.1' # 0.openwrt.pool.ntp.org uci add_list system.ntp.server='213.222.217.11' # 1.openwrt.pool.ntp.org uci add_list system.ntp.server='80.50.102.114' # 2.openwrt.pool.ntp.org uci add_list system.ntp.server='193.219.28.60' # 3.openwrt.pool.ntp.org uci commit system
LAN clients should use Dnsmasq as a primary resolver. Dnsmasq forwards DNS queries to dnscrypt-proxy2 which encrypts DNS traffic.
Note: These are the recommended options from the official DNSCrypt guide for OpenWrt on GitHub.
Note: Beware that the distributed configuration includes an activated block-names.txt
. If you experience problems with some names, match them against this file first.
Optional steps suggested by the official DNSCrypt guide for OpenWrt on GitHub:
# Optional: Enable printing logs in syslog sed -i "183 s/.*/use_syslog = true/" /etc/dnscrypt-proxy2/*.toml service dnscrypt-proxy restart # Optional: Disable ISP's DNS server uci set network.wan.peerdns='0' uci set network.wan6.peerdns='0' uci commit network # Optional: Force LAN clients to send DNS queries to dnscrypt-proxy: ## 1. Divert-DNS, port 53 uci add firewall redirect uci set firewall.@redirect[-1].dest='lan' uci set firewall.@redirect[-1].target='DNAT' uci set firewall.@redirect[-1].name='Divert-DNS, port 53' uci set firewall.@redirect[-1].src='wan' uci set firewall.@redirect[-1].src_dport='53' uci set firewall.@redirect[-1].dest_port='53' uci commit firewall ## 2. Block DNS-over-TLS over port 853 uci add firewall rule uci set firewall.@rule[-1].name='Reject-DoT,port 853' uci add_list firewall.@rule[-1].proto='tcp' uci set firewall.@rule[-1].src='lan' uci set firewall.@rule[-1].dest='wan' uci set firewall.@rule[-1].dest_port='853' uci set firewall.@rule[-1].target='REJECT' uci commit firewall ## 3. Optional: Redirect queries for DNS servers running on non-standard ports. For example: 5353 ## Warning: don't use this one if you run an mDNS server uci add firewall redirect uci set firewall.@redirect[-1].dest='lan' uci set firewall.@redirect[-1].target='DNAT' uci set firewall.@redirect[-1].name='Divert-DNS, port 5353' uci set firewall.@redirect[-1].src='lan' uci set firewall.@redirect[-1].src_dport='5353' uci set firewall.@redirect[-1].dest_port='53' uci commit firewall /etc/init.d/firewall reload
Testing
Verify domain name resolution with nslookup.
nslookup openwrt.org localhost
Check your DNS provider and test DNSSEC validation.
Troubleshooting
Collect and analyze the following information.
# Restart services service log restart; service dnsmasq restart; service dnscrypt-proxy restart # Log and status logread -e dnsmasq; netstat -l -n -p | grep -e dnsmasq logread -e dnscrypt-proxy; netstat -l -n -p | grep -e dnscrypt-proxy # Runtime configuration pgrep -f -a dnsmasq; pgrep -f -a dnscrypt-proxy head -v -n -0 /etc/resolv.* /tmp/resolv.* /tmp/resolv.*/* # Persistent configuration uci show dhcp; grep -v -e "^\s*#" -e "^\s*$" /etc/dnscrypt-proxy2/dnscrypt-proxy.toml
Extras
DoH and DNSCrypt provider
dnscrypt-proxy2 is configured with Google DNS and Cloudflare DNS by default. You can change it to Google DNS or any other DoH or DNSCrypt provider. Use resolvers supporting DNSSEC validation if necessary. Specify several resolvers to improve fault tolerance.
# Configure DoH or DNSCrypt provider # First, we need to set up a list of servers to use, example: (you have to change "exampledns" for the name of the DNS provider) sed -i "32 s/.*/server_names = ['exampledns', 'exampledns2']/" /etc/dnscrypt-proxy2/*.toml service dnscrypt-proxy restart # Or you can also use only one server, example: sed -i "32 s/.*/server_names = ['cloudflare']/" /etc/dnscrypt-proxy2/*.toml service dnscrypt-proxy restart
ODoH protocol
ODoH (Oblivious DNS-over-HTTPS) prevents servers from learning anything about client IP addresses, by using intermediate relays dedicated to forwarding encrypted DNS data. Instead of directly sending a query to a target DoH server, the client encrypts it for that server, but sends it to a relay. An ODoH relay can only communicate with an ODoH server and an ODoH client. Relays can't get responses from a generic DoH server that doesn't support ODoH. You can change the ODoH servers and ODoH relays to any other.
# Enable ODoH on dnscrypt-proxy2 sed -i -e "s/.*odoh_servers.*/odoh_servers = true/; 689,700 s/#//" /etc/dnscrypt-proxy2/*.toml # Configure "ODoH servers" and "ODoH relays" odoh_servers="['odoh-cloudflare', 'odoh-crypto-sx']" odoh_relays="['odohrelay-crypto-sx', 'odohrelay-koki-bcn']" sed -i -e "32 s/.*/server_names = $odoh_servers/; 795 s/.*/routes = [/; 797 s/.*/ { server_name='*', via=$odoh_relays }/; 798 s/.*/]/" /etc/dnscrypt-proxy2/*.toml service dnscrypt-proxy restart
More information about ODoH protocol: Improving DNS Privacy with Oblivious DoH in 1.1.1.1
Caveats: The Oblivious DNS-over-HTTPS protocol is still a work in progress. Servers and relays may not be very stable.