The value of any asset is equal to the present value of all future cash flow is the concept being relied on when valuing a firm using the DCF valuation method. Does the interest rate factor in your model? If so, how does the interest rate factor in your model? There are at least two ways the interest rates are accounted for in a DCF valuation model.
We discuss the different ways interest rates can factor into your DCF valuation model on this page.