Can't override clientCache@cacheControlMaxAge

I have the following in my web.config: <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="30.00:00:00" cacheControlCustom="public"></clientCache> However, the browser reports the following in the response: Cache-Control:public,max-age=86400 Even stranger, the applicationHost.config has it as follows: <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="7.00:00:00" /> So I'm not sure where the 86400 (1 day) is coming from, and how to override it?