ASP.Net Core 5-Getting the User's IP Address

This is for a "webapp" (aka Razor Pages). It's the kind of app that you'd start with "dotnet new webapp" at the terminal.

Paste this at the top of your model file:

using System.Net;

Paste this before the final brace of your model file:

            public static class HttpContextExtensions
                {
                    public static IPAddress GetRemoteIPAddress(this HttpContext context, bool allowForwarded = true)
                    {
                        if (allowForwarded)
                        {
                            string header = (context.Request.Headers["CF-Connecting-IP"].FirstOrDefault() ?? context.Request.Headers["X-Forwarded-For"].FirstOrDefault());
                            if (IPAddress.TryParse(header, out IPAddress ip))
                            {
                                return ip;
                            }
                        }
                        return context.Connection.RemoteIpAddress;
                    }
                }
        

Last, in the routine where you want to discover it, put this:

string the_ip=HttpContext.GetRemoteIPAddress().ToString();