How to get Client IP address in ASP.NET Core 2.1

Question

I\'m working on ASP.Net Core 2.1 with Angular Template provided by Microsoft Visual Studio 2017. My Client App is working fine. After competition of User Authentication, I want

Answer 1

If I use the Binding Address Localhost:5000 then the IP is returned as "::1" (Localhost IPv6 address). If I bind my Webapi on the IP Address and try to reach it from another client computer, I get Client's IP Address in API Response. There is no need for HTTPAccessor i believe. As per the documentation https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/proxy-load-balancer?view=aspnetcore-2.1, the HttpContext.Connection.RemoteIpAddress is set by XForwardedFor header.

If your application (WEBAPI) is behind a NGINX/Apache Reverse Proxy, you should enable those REV Proxies to send X-Forwarded-For Header address which contains the real IP address of the Client, if you don't setup or process X-Forwarded-For Header, then you would always get either Nulls or Reverse-Proxy Server's IP Address.

The GetHostEntry above has no relation to the HTTP Request directly. GetHostEntry is just a NSLookup tool for API programming and it just tells you the IP Addresses reachable for a particular name, but doesn't tell you from which IP address the Request came to WebApi.

Hope that helps

Answer 2

After spending some time on searching I found my own question answer. Here I'm also sharing the source link from where I can get my answer and detail explanation for how to query a server to obtain the family addresses and the IP addresses it supports.

Code:

IPHostEntry heserver = Dns.GetHostEntry(Dns.GetHostName());
var ip = heserver.AddressList[2].ToString();

Source

Here is my another Question: How to access server variables in ASP.Net Core 2.x Hope this helps for you all.

Answer 3

This works for me on .Net Core 2.2:

IPHostEntry heserver = Dns.GetHostEntry(Dns.GetHostName());

var ipAddress = heserver.AddressList.ToList().Where(p => p.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork).FirstOrDefault().ToString();

Answer 4

It's possible to use the following code:

services.Configure<ForwardedHeadersOptions>(options =>
{
    options.ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto;
});

string remoteIpAddress = HttpContext.Connection.RemoteIpAddress.MapToIPv4().ToString();
if (Request.Headers.ContainsKey("X-Forwarded-For"))
    remoteIpAddress = Request.Headers["X-Forwarded-For"];

Answer 5

If your Kestrel sits behind a reverse proxy like IIS make sure to forward the headers containing the client IP.
This goes into startup:

app.UseForwardedHeaders(new ForwardedHeadersOptions{ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto});

Answer 6

In your Startup.cs, make sure you have a method to ConfigureServices, passing in the IServiceCollection, then register IHttpContextAccessor as a singleton as follows:

public void ConfigureServices(IServiceCollection services)
{
    services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
}

After registering the IHttpContextAccessor in your Startup.cs file, you can inject the IHttpContextAccessor in your controller class and use it like so:

private IHttpContextAccessor _accessor;

public ValuesController(IHttpContextAccessor accessor)
{
    _accessor = accessor;
}

public IEnumerable<string> Get()
{
    var ip = _accessor.HttpContext?.Connection?.RemoteIpAddress?.ToString();
    return new string[] { ip, "value2" };
}