How Do I Prevent MSIE 8 From Reloading PAC File?

Question

Exactly what the title says. I need to stop IE 8 from reloading the PAC file on every request the browser makes.

I only require it to load once per session.

Answer 1

IE should be caching the PAC result per server/host by default and should only be reloading the PAC file when it resolves a host it hasn't talked to on that session, it shouldn't be loading it on every request.

The registry key that controls whether it caches the result by host or not is:

HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings
Value: EnableAutoproxyResultCache
Type: REG_DWORD
Data value: 0 = disable caching; 1 (or key not present) = enable automatic proxy caching (this is the default behavior)

Or you can control it with group policies with the following setting:

User Configuration\Administrative Templates\Windows Components\Internet Explorer
Disable caching of Auto-Proxy scripts