I'm doing some optimization on a new site on our dedicated server. Based on results from Firebug/YSlow, I'm looking at the whole 'Expires Headers' thing and am a bit confused.

Can I set 'Expires Headers' through IIS admin on a directory level? On individual files?

Does simply changing the filename of a resource (images, page, etc.) guarantee that it will be served to returning visitors?

Can any IIS admin pros give any guidance re: pitfalls, what to watch out for, best practices, etc.

What do I need to be aware of with ColdFusion (dynamic) pages?

I've done what research I can but really don't want to screw things up at this point. Any guidance from an IIS Admin pro would be most appreciated.

There is an article that I think you would like that shows more information and explanation into the Expires or a Cache-Control Header for.

http://developer.yahoo.com/performance/rules.html

Hope this helps!