.. _`Google Public DNS`: https://developers.google.com/speed/public-dns
.. _Quad9: https://quad9.net
.. _CloudFlare: https://blog.cloudflare.com/announcing-1111
.. _RADIUS: https://en.wikipedia.org/wiki/RADIUS
.. _FreeRADIUS: https://freeradius.org
.. _`Network Policy Server`: https://en.wikipedia.org/wiki/Network_Policy_Server
.. _RFC2332: https://tools.ietf.org/html/rfc2332
.. _RFC1702: https://tools.ietf.org/html/rfc1702
.. _RFC4301: https://tools.ietf.org/html/rfc4301
.. _PPTP: https://en.wikipedia.org/wiki/Point-to-Point_Tunneling_Protocol