When ISA server delivers the WPAD script, it sets a Cache-Control header with the value "max-age=3000", that means 50 minutes. Internet Explorer rounds this up to 1 hour. So, if you are testing WPAD changes, i.e. you are playing with "Auto Discovery" or "Direct Access", then you will need to be sure to delete the previously acquired WPAD script and resolved WPAD name.
The easiest way to accomplish this is to execute the following steps:
- Clear the Internet Explorer cache completely: ActiveX Controls, Cookies, History, etc..
- Close all instances of Internet Explorer.
- Delete all WPAD script instances. Open a command window as administrator and type the following command:
del \wpad*.dat /s
- Clear the DNS and Netbios name caches. Open a command window as administrator and type the following commands:
You should now have a clean starting point for testing WPAD script changes.