I am attempting to setup a example using the ESP8266 wifi but when compiling the code it keeps failing with DNSServer.h not found after lots of searching i am unable to locate the download can someone please give me link on where i can download the needed files to install into the libraries.
It's in the ESP8266 core for Arduino.
This package on GitHub:-
If you read the linked page, it's apparently installable via the Arduino "Boards Manager", by entering the appropriate URL into the "Additional Board Manager URLs" field in >File >Preferences
I think you can safely ignore the instruction to install IDE V1.6.8, (it's not too stable). Either IDE V1.6.5 or V1.6.9 would be better.
The URL to enter:-
http://arduino.esp8266.com/stable/package_esp8266com_index.json