To make whole home network use OpenDNS I need to change only 3 files on my OpenWRT router.
First step – resolv.conf
Create /etc/resolv.conf.opendns with OpenDNS servers addresses, eg:
nameserver 208.67.222.222
nameserver 208.67.220.220
nameserver 208.67.220.220
Make sure /etc/resolv.conf defines 127.0.0.1 as a name server.
Second step – dnsmasq
In /etc/config/dhcp set resolvfile variable:
option resolvfile '/etc/resolv.conf.opendns'
Restart dnsmasq with:
# /etc/init.d/dnsmasq restart