Override single attribute in machine.config

I was wondering if it's possible to override just an attribute of a tag in machine.config ?

More exactly I want to set the domain attribute of in machine.config, as it differs from my production server and my development server.

I tried just adding the tag to machine.config, but alas it doesn't seem to have an effect.

in machine.config I added:

<authentication>
  <forms domain=".foo.com" />
</authenticaion>

EDIT:

Since web.config overrides machine.config, the question is rather how I avoid losing my domain attribute on the ta开发者_如何学Cg, when forms is also defined in web.config ?

You can override values of your machine.config by entering values into web.config. Web.config and machine.config will be merged at runtime. But web.config will override configured values within the web.config.

Ok normally if you leave out the authentication section of your web.config the entry of your machine.config is used.