How to secure dll files in asp.net mvc?

Hello Everyone,

I am developing an asp.net MVC 5 Web API application using c# for one of our clients. Now I am going to host the application on one of our customer's local servers (Windows server 2008 R2).

So I want to know how can I prevent getting logic from my .dll files and get the source code of my application? I need to secure my dlls to protect my business logic and my own code from being used by our competitors, so if someone wants to read the dll files then he can't read it.

so can anyone advise what are the approaches I can follow to secure my dll files from being reversed engineered?

Thanks.