How do I get client IP address in ASP.NET Core?

Question

Can you please let me know how to get client IP address in ASP.NET when using MVC 6. Request.ServerVariables["REMOTE_ADDR"] does not work.

Answer 1

The API has been updated. Not sure when it changed but according to Damien Edwards in late December, you can now do this:

var remoteIpAddress = request.HttpContext.Connection.RemoteIpAddress;

Answer 2

Note: The Microsoft.AspNetCore.HttpOverrides package (among many others) is deprecated as of May 2022. See this answer on how to do it instead.

---

In project.json add a dependency to:

"Microsoft.AspNetCore.HttpOverrides": "2.2.0"

In Startup.cs, in the Configure() method add:

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

And, of course:

using Microsoft.AspNetCore.HttpOverrides;

Then, I could get the ip by using:

Request.HttpContext.Connection.RemoteIpAddress

In my case, when debugging in VS I got always IpV6 localhost, but when deployed on an IIS I got always the remote IP.

Some useful links: How do I get client IP address in ASP.NET Core? and RemoteIpAddress is always null

The ::1 is maybe because of:

Connections termination at IIS, which then forwards to Kestrel, the v.next web server, so connections to the web server are indeed from localhost. (https://stackoverflow.com/a/35442401/5326387)

As of Dec 2020 the latest version is 2.2.0

In .NET 5 the namespace is Microsoft.AspNetCore.Builder.

Answer 3

Some fallback logic can be added to handle the presence of a Load Balancer.

Also, through inspection, the X-Forwarded-For header happens to be set anyway even without a Load Balancer (possibly because of additional Kestrel layer?):

public string GetRequestIP(bool tryUseXForwardHeader = true)
{
    string ip = null;

    // todo support new "Forwarded" header (2014) https://en.wikipedia.org/wiki/X-Forwarded-For

    // X-Forwarded-For (csv list):  Using the First entry in the list seems to work
    // for 99% of cases however it has been suggested that a better (although tedious)
    // approach might be to read each IP from right to left and use the first public IP.
    // http://stackoverflow.com/a/43554000/538763
    //
    if (tryUseXForwardHeader)
        ip = GetHeaderValueAs<string>("X-Forwarded-For").SplitCsv().FirstOrDefault();

    // RemoteIpAddress is always null in DNX RC1 Update1 (bug).
    if (ip.IsNullOrWhitespace() && _httpContextAccessor.HttpContext?.Connection?.RemoteIpAddress != null)
        ip = _httpContextAccessor.HttpContext.Connection.RemoteIpAddress.ToString();

    if (ip.IsNullOrWhitespace())
        ip = GetHeaderValueAs<string>("REMOTE_ADDR");

    // _httpContextAccessor.HttpContext?.Request?.Host this is the local host.

    if (ip.IsNullOrWhitespace())
        throw new Exception("Unable to determine caller's IP.");

    return ip;
}

public T GetHeaderValueAs<T>(string headerName)
{
    StringValues values;

    if (_httpContextAccessor.HttpContext?.Request?.Headers?.TryGetValue(headerName, out values) ?? false)
    {
        string rawValues = values.ToString();   // writes out as Csv when there are multiple.

        if (!rawValues.IsNullOrWhitespace())
            return (T)Convert.ChangeType(values.ToString(), typeof(T));
    }
    return default(T);
}

public static List<string> SplitCsv(this string csvList, bool nullOrWhitespaceInputReturnsNull = false)
{
    if (string.IsNullOrWhiteSpace(csvList))
        return nullOrWhitespaceInputReturnsNull ? null : new List<string>();

    return csvList
        .TrimEnd(',')
        .Split(',')
        .AsEnumerable<string>()
        .Select(s => s.Trim())
        .ToList();
}

public static bool IsNullOrWhitespace(this string s)
{
    return String.IsNullOrWhiteSpace(s);
}

Assumes _httpContextAccessor was provided through DI.

Answer 4

I found that, some of you found that the IP address you get is :::1 or 0.0.0.1

This is the problem because of you try to get IP from your own machine, and the confusion of C# that try to return IPv6.

So, I implement the answer from @Johna (https://stackoverflow.com/a/41335701/812720) and @David (https://stackoverflow.com/a/8597351/812720), Thanks to them!

and here to solution:

1. add Microsoft.AspNetCore.HttpOverrides Package in your References (Dependencies/Packages)

2. add this line in Startup.cs

   public void Configure(IApplicationBuilder app, IHostingEnvironment env)
   {
       // your current code
   
       // start code to add
       // to get ip address
       app.UseForwardedHeaders(new ForwardedHeadersOptions
       {
       ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto
       });
       // end code to add
   
   }
   

3. to get IPAddress, use this code in any of your Controller.cs

   IPAddress remoteIpAddress = Request.HttpContext.Connection.RemoteIpAddress;
   string result = "";
   if (remoteIpAddress != null)
   {
       // If we got an IPV6 address, then we need to ask the network for the IPV4 address 
       // This usually only happens when the browser is on the same machine as the server.
       if (remoteIpAddress.AddressFamily == System.Net.Sockets.AddressFamily.InterNetworkV6)
       {
           remoteIpAddress = System.Net.Dns.GetHostEntry(remoteIpAddress).AddressList
   .First(x => x.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork);
       }
       result = remoteIpAddress.ToString();
   }
   

and now you can get IPv4 address from remoteIpAddress or result

Answer 5

In ASP.NET 2.1, In StartUp.cs Add This Services:

services.AddHttpContextAccessor();
services.TryAddSingleton<IActionContextAccessor, ActionContextAccessor>();

and then do 3 step:

1. Define a variable in your MVC controller

   private IHttpContextAccessor _accessor;
   

2. DI into the controller's constructor

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

3. Retrieve the IP Address

   _accessor.HttpContext.Connection.RemoteIpAddress.ToString()
   

This is how it is done.

Answer 6

You can use the IHttpConnectionFeature for getting this information.

var remoteIpAddress = httpContext.GetFeature<IHttpConnectionFeature>()?.RemoteIpAddress;

Answer 7

var remoteIpAddress = HttpContext.Features.Get<IHttpConnectionFeature>()?.RemoteIpAddress;

Answer 8

As of September 2021 - ASP.NET Core (5.x) MVC project allowed me to get the IP Address this way in my controller:

Request.HttpContext.Connection.RemoteIpAddress

Quite a bit more simple now than in the past, it seems.

Adding A Bit Of Clarity

I originally mentioned that this is available in a MVC project inside my HttpController.

The Request object is available because my DataController is derived from the ASP.NET MVC Controller class.

Here's snippet of Microsoft's base class code where that Request and HttpRequest is made available via inheritance to classes which derive from it.

#region Assembly Microsoft.AspNetCore.Mvc.Core, Version=6.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60
// Microsoft.AspNetCore.Mvc.Core.dll
#endregion

#nullable enable

using System.Linq.Expressions;
using System.Runtime.CompilerServices;
using System.Security.Claims;
using System.Text;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Mvc.Infrastructure;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
using Microsoft.Net.Http.Headers;

namespace Microsoft.AspNetCore.Mvc
{
    //
    // Summary:
    //     A base class for an MVC controller without view support.
    [Controller]
    public abstract class ControllerBase
    {
        protected ControllerBase();

        //
        // Summary:
        //     Gets the Microsoft.AspNetCore.Http.HttpResponse for the executing action.
        public HttpResponse Response { get; }
        //
        // Summary:
        //     Gets the Microsoft.AspNetCore.Http.HttpRequest for the executing action.
        public HttpRequest Request { get; }

Answer 9

This works for me (DotNetCore 2.1)

[HttpGet]
public string Get() 
{
    var remoteIpAddress = HttpContext.Connection.RemoteIpAddress;
    return remoteIpAddress.ToString();
}

Answer 10

Running .NET core (and probably .NET 6/7) on IIS behind a Load balancer did not work with other suggested solutions.

Manually reading the X-Forwarded-For header does. This code assumes the header contains one IP.

IPAddress ip;
var headers = Request.Headers.ToList();
if (headers.Exists((kvp) => kvp.Key == "X-Forwarded-For"))
{
    // when running behind a load balancer you can expect this header
    var header = headers.First((kvp) => kvp.Key == "X-Forwarded-For").Value.ToString();
    // in case the IP contains a port, remove ':' and everything after
    ip = IPAddress.Parse(header.Remove(header.IndexOf(':')));
}
else
{
    // this will always have a value (running locally in development won't have the header)
    ip = Request.HttpContext.Connection.RemoteIpAddress;
}

Edit: Thanks to @JawadAlShaikh and @BozoJoe for pointing out the IP can contain a port and the X-Forwarded-For can contain multiple IPs.

Answer 11

In my case, I have DotNet Core 2.2 Web App running on DigitalOcean with docker and nginx as reverse proxy. With this code in Startup.cs I can get the client IP

app.UseForwardedHeaders(new ForwardedHeadersOptions
        {
            ForwardedHeaders = ForwardedHeaders.All,
            RequireHeaderSymmetry = false,
            ForwardLimit = null,
            KnownNetworks = { new IPNetwork(IPAddress.Parse("::ffff:172.17.0.1"), 104) }
        });

::ffff:172.17.0.1 was the ip that I was getting before using

Request.HttpContext.Connection.RemoteIpAddress.ToString();

Answer 12

NOTE: When using localhost the IP address is always "0.0.0.1" but when I host the application on AWS EC2 instance using Nginx I receive the correct Ip address.

Add the below package to your project:

"Microsoft.AspNetCore.HttpOverrides": "2.2.0"

then add the following in the Configure() method in Startup.cs (Make sure to put it before app.UseStaticFiles() and app.UseRouting())

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

and then in your controller class you can get the IP address using the following code:

IPAddress remoteIpAddress = Request.HttpContext.Connection.RemoteIpAddress?.MapToIPv4()?.ToString();

Answer 13

As per the official documentation, if you are using Apache or Nginx integration, following code should be added to the Startup.ConfigureServices method.

// using Microsoft.AspNetCore.HttpOverrides;

    services.Configure<ForwardedHeadersOptions>(options =>
    {
        options.ForwardedHeaders = ForwardedHeaders.XForwardedFor | 
            ForwardedHeaders.XForwardedProto;
        // Only loopback proxies are allowed by default.
        // Clear that restriction because forwarders are enabled by explicit 
        // configuration.
        options.KnownNetworks.Clear();
        options.KnownProxies.Clear();
    });

and then on top of everything, in Configure method use

app.UseForwardedHeaders();

Further suppose in nginx conf file, inside a location, use

proxy_set_header   Host $host;
proxy_set_header   X-Real-IP $remote_addr;
proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header   X-Forwarded-Host $server_name;

Now the first entry in the X-Forwarded-For will be the real client IP.

IMPORTANT: If you want to secure the app and not allow an attacker inject X-Forwarded-For, Please read this answer.

Please see Forward the scheme for Linux and non-IIS reverse proxies, Configure Nginx and Dealing with invalid headers

Answer 14

In .NET 5 I use this to retrieve the client IP via a container on AWS fargate.

public static class HttpContextExtensions
{
    //https://gist.github.com/jjxtra/3b240b31a1ed3ad783a7dcdb6df12c36

    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;
    }
}

You call it like this:

var ipFromExtensionMethod = HttpContext.GetRemoteIPAddress().ToString();

Source

Answer 15

Short version of @crokusek's answer

public string GetUserIP(HttpRequest req)
{
    var ip = req.Headers["X-Forwarded-For"].FirstOrDefault();

    if (!string.IsNullOrWhiteSpace(ip)) ip = ip.Split(',')[0];

    if (string.IsNullOrWhiteSpace(ip)) ip = Convert.ToString(req.HttpContext.Connection.RemoteIpAddress);

    if (string.IsNullOrWhiteSpace(ip)) ip = req.Headers["REMOTE_ADDR"].FirstOrDefault();

    return ip;
}

Answer 16

Running ASP.NET Core 2.1 behind a Traefik reverse Proxy on Ubuntu, I need to set its gateway IP in KnownProxies after installing the official Microsoft.AspNetCore.HttpOverrides package

        var forwardedOptions = new ForwardedHeadersOptions {
            ForwardedHeaders = ForwardedHeaders.XForwardedFor,
        };
        forwardedOptions.KnownProxies.Add(IPAddress.Parse("192.168.3.1"));
        app.UseForwardedHeaders(forwardedOptions);

According to the documentation, this is required if the reverse proxy is not running on localhost. The docker-compose.yml of Traefik has assigned a static IP address:

networks:
  my-docker-network:
    ipv4_address: 192.168.3.2

Alternatively, it should be enough to make sure a known network is defined here to specify its gateway in .NET Core.

Answer 17

First Add

Microsoft.AspNetCore.Http
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();

in ConfigureServices in Startup.cs Then Add the following code in your controller

   private IHttpContextAccessor _accessor;
    
  public LoginController(IHttpContextAccessor accessor)
            {
              _accessor = accessor;
            }

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

Hope this will work for you

Answer 18

First, in .Net Core 1.0 Add using Microsoft.AspNetCore.Http.Features; to the controller Then inside the relevant method:

var ip = HttpContext.Features.Get<IHttpConnectionFeature>()?.RemoteIpAddress?.ToString();

I read several other answers which failed to compile because it was using a lowercase httpContext, leading the VS to add using Microsoft.AspNetCore.Http, instead of the appropriate using, or with HttpContext (compiler is also mislead).

Answer 19

try this:

string remoteHost = $"{httpContext.Connection.RemoteIpAddress}:{httpContext.Connection.RemotePort}";

Answer 20

You can also get IP from an external service.

public string GetIP()
{
    HttpClient client = new HttpClient();
    var result = client.GetStringAsync("https://jsonip.com/").Result;
    var ip = JsonSerializer.Deserialize<RemoteIPDto>(result.ToString()).IP;
    return ip;
}

Where RemoteIPDto class is

public class RemoteIPDto
{
    [JsonPropertyName("ip")]
    public string IP { get; set; }
    [JsonPropertyName("geo-ip")]
    public string GeoIp { get; set; }
    [JsonPropertyName("API Help")]
    public string ApiHelp { get; set; }
}

Answer 21

From this link, there is a better solution.

In Startup.cs, we need to add service-

public void ConfigureServices(IServiceCollection services)
{
    ........
    services.AddHttpContextAccessor();
    ........
}

Then in any controller or any place, we need to use it via dependency injection like this-

private IHttpContextAccessor HttpContextAccessor { get; }

public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options, IWebHostEnvironment env, IHttpContextAccessor httpContextAccessor)
        : base(options)
{
    Environment = env;
    HttpContextAccessor = httpContextAccessor;
    //this.Database.EnsureCreated();
}

And then get IP like this-

IPAddress userIp = HttpContextAccessor.HttpContext.Connection.RemoteIpAddress;

Answer 22

You can also get both IP Address and the location using the api.db-ip.com web service.

The service is free, but it has a limitation: 1,000 requests per day.

public string GetRemoteIP()
{
    HttpClient client = new HttpClient();
    var result = client.GetStringAsync("https://api.db-ip.com/v2/free/self").Result;
    var ip = JsonSerializer.Deserialize<RemoteIPDto>(result.ToString()).IP;
    return ip;
}
public static string GetUserAddress()
{
      HttpClient client = new HttpClient();
      var result = client.GetStringAsync("https://api.db-ip.com/v2/free/self").Result;
      var location = result.ToString();
      return remoteAddress;
}

where RemoteIPDto class is

public class RemoteIPDto
{
    [JsonPropertyName("ipAddress")]
    public string IP { get; set; }
    [JsonPropertyName("continentCode")]
    public string ContinentCode { get; set; }
    [JsonPropertyName("continentName")]
    public string ContinentName { get; set; }
    [JsonPropertyName("countryCode")]
    public string CountryCode { get; set; }
    [JsonPropertyName("countryName")]
    public string CountryName { get; set; }
    [JsonPropertyName("city")]
    public string City { get; set; }
}

Answer 23

I am using asp.net core 6 and this worked for me

var remoteIpAddress = HttpContext.Connection.RemoteIpAddress;

as answers suggested, it will give you the local IP address on the development environment but you will get the real IP when deploying a server.

Answer 24

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Http.Features;

public string GetClientIPAddress(HttpContext context)
    {
        string ip = string.Empty;
if (!string.IsNullOrEmpty(context.Request.Headers["X-Forwarded-For"]))
        {
            ip = context.Request.Headers["X-Forwarded-For"];
        }
        else
        {
            ip = context.Request.HttpContext.Features.Get<IHttpConnectionFeature>().RemoteIpAddress.ToString();
        }
        return ip;
    }

Where you want to get Ip address;

GetClientIPAddress(HttpContext);

Answer 25

try this.

var host = Dns.GetHostEntry(Dns.GetHostName());
        foreach (var ip in host.AddressList)
        {
            if (ip.AddressFamily == AddressFamily.InterNetwork)
            {
                 ipAddress = ip.ToString();
            }
        }

Answer 26

To get IP address and hostname in .NET Core, put the following code in the controller:

var addlist = Dns.GetHostEntry(Dns.GetHostName());
string GetHostName = addlist.HostName.ToString();
string GetIPV6 = addlist.AddressList[0].ToString();
string GetIPV4 = addlist.AddressList[1].ToString();