Help getting the remote computer name

Hi guys, I am in big time need of solve the problem I am currently having trying to get the remote client computer name, I have tried the following

1st option

Request.UserHostName.Trim() works good within the Visual Studio IDE but it is deployed to Windows 2016 IIS8 hosting I get the Public IP instead.

2nd Option

I also tried the following which also works within the visual Studio IDE but after deployed

I get an error message "no host found"

string[] computer_name = System.Net.Dns.GetHostEntry(Request.ServerVariables["REMOTE_ADDR"]).HostName.Split(new Char[] { '.' });

String ecname = System.Environment.MachineName;

return computer_name[0].ToString();

3rd Option

I also tried the following which also works within the visual Studio IDE but after deployed

I get the server name instead

System.Net.Dns.GetHostEntry(Dns.GetHostName()).HostName.ToString()

Any Idea How to get the remote client computer name with ASP.NET C# Framework 4.0

without using ActiveX

I will really appriciate the right and working answer.

TIA