Here 3 patches to install in recovery to use alternativeDNS.
Every patch install an init.d script:
and so to "uninstall" the patch just delete the file DNS.
To install these patches the rom must have the support for the init.d scripts, this way to set alternative DNS has been tested on KitKat but should work on every Android version, this way to set alternative DNS server has been tested on KitKat but should work on every android version.
- Comodo Secure DNS
- Google Public DNS
once you decided which to use simply download and install the corresponding patch.