app.config used by DLL

Good morning,

I am working on C# project and I am facing some difficulties.

See below the architecture of the project :

My dlls which contain some objects and methods.
A main program which uses my dlls.

I use objects and methods in the main program. At runtime, these methods use external dlls. At the deployment level, my dlls have to be located next to external dlls, especially for calls to remote database servers. Information allowing to interact with external dlls is written in the app.config file of the main program.

The problem is that I'm currently using an exe to test my dlls but my dlls will be, int the future, deployed in an customer environment and not necessarily with an executable.

My question is how to make and use an app.config that is linked to my dlls and not to an executable ?

Thank you in advance for any help.