IP Address
In asp.net full-fat version you could do this:
Request.UserHostAddress
Now you must do this:
Request.HttpContext.Connection.RemoteIpAddress.ToString()
But hey, it's kinda cool, because Request.HttpContext.Connection.RemoteIpAddress is a real object...
It's of the abstract type 'IPAddress' which is a fun little class, resembling as it does the general result you would achieve if you ate a whole box of 'IPv6' and then vomited all over the editor.
But... alas... when using Kestrel and a forwarding web server (such as nginx) you will find that
Request.HttpContext.Connection.RemoteIpAddress.ToString() == "127.0.0.1"
...ALL the time, which is not what you wanted to see. (Or it could be "::1" which is no better)
This is because original IP request is terminated by nginx, and a new request is sent to your application. Instead if we configure nginx to put the original IP into a request header, and we look at that request header, then we will see the original remote IP address of the caller. Here's the nginx config details...
proxy_set_header X-Real-IP $remote_addr;
(See article on nginx to work out exactly where to put that)
In .net core MVC you can then:
var ipaddress = Request.HttpContext.Connection.RemoteIpAddress.ToString();
if (Request.Headers["X-Real-IP"].Count() > 0)
{
ipaddress = Request.Headers["X-Real-IP"];
}