DoH (dns-over-https) python3 utillites for testing

WARNING: demonstration, research, development and testing purposes ONLY!

if you need working stuff: https://github.com/facebookarchive/doh-proxy

requirements

• dnspython json urllib

to install these for user, use:

$ pip3 install --break-system-packages --user [MODULES...]

What are all of these?

client-side:

• doh-client.py - DoH client, command-line

server-side (a.k.a stub):

• dns-query.py - DoH server, CGI (Apache), NOTE: running with no arguments starts this mode!
• ?dns-query-fcgi.py? - DoH server, FastCGI, talking through fcgi.sock
• ? - DoH server, WSGI/ASGI w/e this is...
• [?] ? - DoH server, standalone or reverse-proxy, if FCGI/WSGI/ASGI stuff feels slow
• [?] ? - DoH server in C/C++, if python3 feels slow
• [?] ...wrap every example, so that it can serve_forever()

other:

• dns-query.conf - Apache CGI conf.d/ drop-in example

What are all of these FOR???!!!

• plain-DNS queries over :53/udp is not secure, can't be trusted and leak data
• opt. 0: DNS-over-TLS to :853/tcp can be used to trusted nameservers (cuddleflare, oogle)
• opt. 1: setup DoH-proxy on router and block outgoing connections in firewall on your router
• opt. 2: setup encrypted WireGuard tunnel to some VPS/VDS and use it's nameserver as the primary one

Examples

query is DNS-wire message in modified base64, see: dohwg/draft-ietf-doh-dns-over-https#30 (comment)

FIXME: you can get such b64 string like this:

$ nc -lu 10053 | base64 | sed '/[=]+$//g' | tr '+=' '_/' </dev/null &
$ dig github.com -p 10053 @127.0.0.1 &>/dev/null 2>&1

name= is (non-RFC) addition for debugging

$ ./doh-client.py name=github.com

/dev/stdin is read to answer POST requests, hence </dev/null

$ ./dns-query.py dns=AAABAAABAAAAAAAABmdpdGh1YgNjb20AAAEAAQ </dev/null
$ QUERY_STRING=dns=AAABAAABAAAAAAAABmdpdGh1YgNjb20AAAEAAQ ./dns-query.py </dev/null
$ echo dns=AAABAAABAAAAAAAABmdpdGh1YgNjb20AAAEAAQ | ./dns-query.py

Links

• WGSI: https://en.wikipedia.org/wiki/Web_Server_Gateway_Interface
• Caddy FastCGI example: https://github.com/tonyallan/python3-experiments/tree/main/caddy-server-fastcgi

LICENSE

• Public Domain