Can we use Authentication in 'Forms' and as well in 'Windows' for a .net web application

Question

We have an application in Access for UI and MS Sql server as Database server. We now decided to build a new application in web application for UI. This web application is only used by the employees who work for the company. But later we decided to host this web application on outside server. So the user (from this company only.) can able to login anywhere in the world. First I thought creating the web application using 'windows' authentication thinking we may be using it as an intranet web application. But now my manager asked me to use both 'Forms' and as well as 'Windows' for using this application and this web application will be hosted on outside server. I really don't catch his point of using both types of authentication.

Please help me is there any ways to use both authentication methods and please also suggest me why we might need to use both authentication methods. If so could you please help me with some instructions of using the both authentication types. Thank you so much for taking time to read and understand my question and helping me in this regard.

Answer 1

@Will explained in his comment as to why both forms of authentication is preferred. The following article shows one way to implement what you need.

You may also want to check the following article to better understand how Windows Authentication works.