Ensuring Windows Server 2016/2019 Is Properly Configured to Accept Requests from an FTP Client

Question

I have a C# program that makes it easy to transfer files using the ftp protocol. It works fine on Server A. But on Server B it throws an exception after the data channel is "connected," at the point where it tries to "connect" the control channel. I have configured the ftp feature under IIS on the Server B so that all available port numbers are available to be used. Every single one. Yet I get a timeout. What else can I try? The firewall is completely disabled. Windows Server 2016 provides the following hint: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond xx.xx.xx.xx:59726

Answer 1

You may want to ask the IIS experts in one of their forums. You can find their forums at iis.net/forums

Answer 2

I did as you suggested. The MVP over there decided my question wasn't worth answering. He blamed my code for the problem and suggested that I contact somebody on an open source site for help. Really? My code works perfectly on Server A. It fails on Server B. Apparently the Ph.D. people who designed File Transfer Protocol could not stop themselves once they invented something that works. Variation upon variation upon variation. I give up.