How to get IP address of the client user?

I used following methods
HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"]
Request.ServerVariables["REMOTE_HOST"]
Request.UserHostAddress
Request.UserHostName
All the above are returning "127.0.0.1", not the actual IP.
The below one returns null.
HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"]

Below one always returns where the application is hosted/running, not the client's IP address.
string strHostName = System.Net.Dns.GetHostName();
string clientIPAddress = System.Net.Dns.GetHostAddresses(strHostName).GetValue(0).ToString();

Please help...
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