https_dns_proxy is a light-weight DNS<-->HTTPS, non-caching translation
proxy for the emerging DoH DNS-over-HTTPS standard. It receives
regular (UDP) DNS requests and issues them via DoH (JSON).
Google's DNS-over-HTTPS service is default, but Cloudflare's service also works with trivial commandline flag changes.
# ./https_dns_proxy -u nobody -g nogroup -d -b 8.8.8.8,8.8.4.4 \
-r "https://dns.google/resolve?"# ./https_dns_proxy -u nobody -g nogroup -d -b 1.1.1.1,1.0.0.1 \
-r "https://cloudflare-dns.com/dns-query?ct=application/dns-json&"Using DNS over HTTPS makes eavesdropping and spoofing of DNS traffic between you and the HTTPS DNS provider (Google/Cloudflare) much less likely. This of course only makes sense if you trust your DoH provider.
- Tiny Size (<30kiB).
- Uses curl for HTTP/2 and pipelining, keeping resolve latencies extremely low.
- Single-threaded, non-blocking select() server for use on resource-starved embedded systems.
- Designed to sit in front of dnsmasq or similar caching resolver for transparent use.
Depends on c-ares, libcurl, libev.
On Debian-derived systems those are libc-ares-dev, libcurl4-{openssl,nss,gnutls}-dev and libev-dev respectively. On Redhat-derived systems those are c-ares-devel, libcurl-devel and libev-devel.
On MacOS, you may run into issues with curl headers. Others have had success when first installing curl with brew.
brew install curl --with-openssl --with-c-ares --with-libssh2 --with-nghttp2 --with-gssapi --with-libmetalink
brew link curl --force
If all pre-requisites are met, you should be able to build with:
$ cmake .
$ make
There is no installer at this stage - just run it.
I maintain a package in the OpenWRT packages repository as well. You can install as follows:
root@OpenWrt:~# opkg update
root@OpenWrt:~# opkg install https_dns_proxy
root@OpenWrt:~# /etc/init.d/https_dns_proxy enable
root@OpenWrt:~# /etc/init.d/https_dns_proxy start
Replace any 'list server' lines in /etc/config/dhcp with:
list server '127.0.0.1#5053'
You may also want to add the line:
noresolv '1'
This prevents dnsmasq from using /etc/resolv.conf DNS servers, leaving only our proxy server.
There is also an externally maintained AUR package for latest git version. You can install as follows:
user@arch:~# yaourt -S https-dns-proxy-git
Just run it as a daemon and point traffic at it. Commandline flags are:
Usage: ./https_dns_proxy [-a <listen_addr>] [-p <listen_port>]
[-d] [-u <user>] [-g <group>] [-b <dns_servers>]
[-r <resolver_url_prefix>] [-e <subnet_addr>]
[-t <proxy_server>] [-l <logfile>] [-x] [-v]+
-a listen_addr Local address to bind to. (127.0.0.1)
-p listen_port Local port to bind to. (5053)
-d Daemonize.
-u user Optional user to drop to if launched as root.
-g group Optional group to drop to if launched as root.
-b dns_servers Comma separated IPv4 address of DNS servers
to resolve resolver host (e.g. dns.google). (8.8.8.8,1.1.1.1,8.8.4.4,1.0.0.1,145.100.185.15,145.100.185.16,185.49.141.37)
-r resolver_url_prefix The HTTPS path to the JSON resolver URL. (https://dns.google/resolve?)
-e subnet_addr An edns-client-subnet to use such as "203.31.0.0/16". ()
-t proxy_server Optional HTTP proxy. e.g. socks5://127.0.0.1:1080
Remote name resolution will be used if the protocol
supports it (http, https, socks4a, socks5h), otherwise
initial DNS resolution will still be done via the
bootstrap DNS servers.
-l logfile Path to file to log to. (-)
-x Use HTTP/1.1 instead of HTTP/2. Useful with broken
or limited builds of libcurl (false).
-v Increase logging verbosity. (INFO)
- Test coverage could be better.
The DoH standard is still evolving. Because responses are translated into JSON, there is room for error in encoding and parsing response types - particularly the less common ones.
For this reason, I tend to believe DNS-over-TLS is a better long-term strategy for the industry, but proxy clients aren't yet readily available.
Note that fundamental differences (binary vs JSON encoding) mean this software does not and will not support DNS-over-TLS.
- Aaron Drew (aarond10@gmail.com)