changing dns settings on android - not working
First you must have dnscrypt installed.
These scripts require root access:

#!/bin/sh
#root is required 

#daemonize dnscrypt
dnscrypt-proxy --daemonize --resolver-address=208.67.220.220:443 --provider-name=2.dnscrypt-cert.opendns.com --provider-key=B735:1140:206F:225D:3E2B:D822:D7FD:691E:A1C3:3CC8:D666:8D0C:BE04:BFAB:CA43:FB79

#this will redirect dns query traffics to localhost
iptables -t nat -A OUTPUT -p udp --dport 53 -j DNAT --to-destination 127.0.0.1


If you want to restore DNS to default, run this:

#!/bin/sh
iptables -t nat -D OUTPUT -p udp --dport 53 -j DNAT --to-destination 127.0.0.1