ASP.net VB - IIS Download File from Not IIS Server

Hello,

I have a web page with 2 hyperlinks on an IIS Server.  They want the links to download files from a different server.  The files are on a Windows 2012 R2 server.  

How do I do this?  And what permissions need to be set up?

The file has a .twb & .twbx extension.  Do they have to be registered as a MIME type in IIS Manager?  If they do, should the MIME Type be application/????  or is there a generic MIME Type?   I can Zip the .twb file but can't zip the .twbx one.

Working with IIS 8.5.  This web works with 1 pool using the Network Service account.

Thanks