Checking

Checking that your DNS traffic is encrypted and authenticated

Once everything has been setup, if you want to verify that your DNS traffic is actually encrypted and authenticated, here are a couple things you can try:

Stop or pause the proxy

On Unix systems, the following command will pause the proxy:

pkill -STOP dnscrypt-proxy

If applications cannot resolve anything now (e.g. no website is available and/or reachable), it probably means that all your DNS traffic was going through the proxy, and was therefore encrypted and authenticated.

To resume execution, use the following command:

pkill -CONT dnscrypt-proxy

Alternatively, you can completely stop and restart service, using e.g. systemd systemctl(1) utility (which is the service manager found in distributions, that have made the switch to systemd) or service(8) command (which works even for distributions, that have migrated to systemd).

On Windows systems, you can stop/start the service.

Block a domain

Add a filter to block a name that is very likely to resolve under normal circumstances.

If you can't access it any more, it means that your DNS traffic is using the proxy, and is therefore encrypted. If you still do, then make sure to flush your DNS cache and restart dnscrypt-proxy service.

Enable query logging

Enable query logging, use your device normally, and check that the log file gets filled by queries you just made.

Use third-party tools

The command-line tool tcpdump can be used to see if there is outgoing non-encrypted traffic:

sudo tcpdump -n dst port 53 and \
  'not dst net (::1 or 10 or 127 or 172.16/12 or 192.168/16)'

Verify DNS provider via DNS Leak test

Another thing User can do, to verify if DNSCrypt-Proxy works is to perform simple DNS Leak test. It can be done by using dnsleaktest.com website. Differences between Standard and Extended tests can be found here: Standard vs Extended.

Below is an example output of an extended DNS Leak test, with three servers configured via server_names option found in dnscrypt-proxy.toml file. Here they are: meganerd (DNSCrypt server by MegaNerd.nl, hosted in Amsterdam), scaleway-fr (DNSCrypt servers donated by Scaleway.com, maintained by Frank Denis) and doh-fi-snopyta (DoH Server in Finland, run by Noah Seefried).

,-------------------------------------------------------------------------------------------------.
| IP 		  | Hostname 		         | ISP 		         | Country                |
'-------------------------------------------------------------------------------------------------'
| 209.250.241.25    jarjar.meganerd.nl. 	   Choopa, LLC 	           Amsterdam, Netherlands |
| 212.47.228.136    scaleway-fr.dnscrypt.info.     Scaleway 	           France                 |
| 95.216.24.230     95.216.24.230. 	           Hetzner Online GmbH     Helsinki, Finland      |
`-------------------------------------------------------------------------------------------------'

The output should contain informations about server or servers configured by User (as in above example) or choosed by DNSCrypt-Proxy itself (based on configuration via available filters in dnscrypt-proxy.toml file, such as require_{dnssec,nolog,nofilter}, and {doh,dnscrypt}_servers options etc.)

If DNS Leak test shows/points to configured servers and methods mentioned above (vide "Block a domain" or "Enable query logging") works as described and have expected results, DNSCrypt-Proxy probably runs okay. (However, if DNS Leak test shows different IP address/server - e.g. of your ISP, it - probably - means, that there is a leak and something is wrong).

NOTE: It seems to be a good idea, to redo DNS Leak test, especially after software (e.g. related with networking etc.), system or web browser updates. We cannot be one hundred percent sure, that if today there isn't a DNS Leak, there won't be one tomorrow.