doh_server

DoH_server

run you own DNS over HTTP2S server

to run quickly run it:

1- make doh directory

2- copy doh-server.conf and edit to suit your needs

3- copy certificate ad private key, for example if you used Letsencrypt with certbot cp /etc/letsencrypt/live/doh.yapily.com/cert.pem doh/ cp /etc/letsencrypt/live/doh.yapily.com/privkey.pem doh/

4- run docker docker run -it -p 443:443 -v /home/mauro/doh:/svc:ro privatesurfing/doh

Docker images available here:

https://hub.docker.com/repository/docker/privatesurfing/doh

Info on browser setup:

https://support.mozilla.org/en-US/kb/firefox-dns-over-https

https://windowsloop.com/enable-dns-over-https-chrome/

https://daniel.haxx.se/blog/2018/06/03/inside-firefoxs-doh-engine/

https://github.com/coredns/coredns/issues/1650

https://pypi.org/project/doh-cli/

FAQs:

• Can I use plain HTTP? No, by design you need HTTPS with a proper certificate

• Shall I run as a service or as container? Being a service exposed over Internet, you should use a container to isolate from the OS, in case you want to run on the plain OS consider to use FireJail.

• Do you think my code is crappy? Help me to write a better one!

• Is it a secure 'container'? The server, a static hardened Go binary, is the only process and it does not perform any outgoing connections other than dns queries

Tips for implementation:

• I use the standard HTTPS port (443) to run this service so my Firefox can use it even behind a corporate firewall (even if having a proxy they can see my surfing activity anyway)

Enhancement to the original project

(https://github.com/m13253/dns-over-https):

• use of the strongest TLS ciphers, random SessionTicket for every connection *

• ability to Skip Ipv6 dns queries to speed up resolution (details here https://github.com/m13253/dns-over-https/pull/19)

• instead of DNS roundrobin I implemented a primitive algorithm to use the fastest DNS server out of the specified pool and continually monitor which server is the fastest

• IP whitelisting, only authorized IP/networks can use it

• /stat page provides upstream DNS latency and relative usage

ToDo

• write some test code

References

• https://blog.ungleich.ch/en-us/cms/blog/2018/08/04/mozillas-new-dns-resolution-is-dangerous/

• https://www.ispreview.co.uk/index.php/2019/09/firefox-says-no-dns-over-https-doh-by-default-for-uk.html

• https://blog.filippo.io/we-need-to-talk-about-session-tickets/

• https://blog.twitter.com/engineering/en_us/a/2013/forward-secrecy-at-twitter.html