How does an IIS App Pool determine its Internet Settings?

I'm specifying a custom identity under which to host a .NET web application, a service account that is part of our Active Directory domain.

When the application runs, it needs to make HTTP requests to other servers. This action causes it to read web and proxy settings from some location, but I can't understand where it goes for this information.

Does it look:

• At the default account's settings on that box?
• At the default profile on the AD server?
• Its own local/roaming profile?
• A combination of the above?
• Somewhere completely different?