How to get the client's IP automatically in ASP.NET CORE

Question

I want to find the user's IP without the user automatically submitting the request from the URL itself. When I do this locally, it returns the correct IP address, but when I publish the web service on the server, this IP becomes the server IP, what should I do?

For example, I have a service at the address https://test.com/api/GetAddress, I call this service in PostMan with the below code and it returns the user's IP address correctly, but when this service is on a site at the address https://sitetest.com/Dashboard/GetHome is called, the server address is returned and the user address is not given to me.

Note that I want to get this IP through the URL itself, because if I put this in the Request and it is received through the developer, it can give any IP to the Api.

I have used both types of code but still the same:

public static string GetClientIp()
    {
        try
        {
            string strHostName = System.Net.Dns.GetHostName();
            IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
            IPAddress ipAddress = ipHostInfo.AddressList
                .FirstOrDefault(a => a.AddressFamily == AddressFamily.InterNetwork);

            return ipAddress?.ToString();
        }
        catch (Exception ex)
        {
            return "0.0.0.0";
        }
        
        //return HttpContext.Current.Connection.RemoteIpAddress?.ToString() ?? "0.0.0.0";
    }

`System.Net.Dns.GetHostName()` tries to get the host name of the server where the code is running. a little research on internet suggest to read [this](https://stackoverflow.com/questions/28664686/how-do-i-get-client-ip-address-in-asp-net-core) and [this](https://www.thecodebuzz.com/get-ip-address-in-asp-net-core-guidelines/) — Chetan, Sep 06 '22 at 06:03
If you pay attention to the commented code, I have done these researches and I don't want to ask questions again. I have tried all the ways written in these articles and this happens again. @Chetan — Mohammad Hasan Salmanian, Sep 06 '22 at 06:14
Can you explain what happens when you try using any of the suggested approach on those link? How they are not solving your issue? — Chetan, Sep 06 '22 at 06:16
Is there a reverse proxy or load balancer before the server? — 4L4M1N, Sep 06 '22 at 07:01
When I call the desired service directly in PostMan, it registers my IP correctly, but when this service is called through a site, the IP address of the server is given to me. @4L4M1N — Mohammad Hasan Salmanian, Sep 06 '22 at 07:43
Who is calling `GetClientIp` method in the code? Who is client and server here? Can you provide bit more information of what you are trying to achieve? — Chetan, Sep 06 '22 at 12:05

Dimitris Maragkos · Answer 1 · 2022-09-06T08:50:38.723

1

Inside a controller get the client ip address using:

var address = Request.HttpContext.Connection.RemoteIpAddress;

If you are using a reverse proxy then you have to use the Forwarded Headers Middleware. Example:

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

This is because the proxy forwards the request to your app so RemoteIpAdress has the ip address of the machine where the proxy is running. Most proxies usually set X-Forwarded-For header with the originating ip address. This middleware reads X-Forwarded-For header and sets the RemoteIpAdress correctly.

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For

edited Sep 06 '22 at 08:50

answered Sep 06 '22 at 08:42

Dimitris Maragkos

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I have done this but it did not work – Mohammad Hasan Salmanian Sep 06 '22 at 10:00
Do you understand the example I wrote? – Mohammad Hasan Salmanian Sep 06 '22 at 10:05
So are you using a reverse proxy or not? If yes, which one? – Dimitris Maragkos Sep 06 '22 at 10:25
My question is, can this method be executed automatically on the web service side without getting the address in the controller client or not? – Mohammad Hasan Salmanian Sep 06 '22 at 10:44
What does 'automatically' mean? A client has to make an http request to server. The http context of the request contain information like the ip address of the client which sent the request. – Dimitris Maragkos Sep 06 '22 at 11:04
Your `GetClientIp` method returns the ip address of the machine where the app is running. – Dimitris Maragkos Sep 06 '22 at 11:14
yes, Finally, I think you understood because I really didn't know how to explain it anymore – Mohammad Hasan Salmanian Sep 06 '22 at 11:19
No I did not understand. Your `GetClientIp` is wrong. It will always return the server ip address. What I'm showing you is how to get the client's ip address and for that you have to use the request http context. If you don't understand I don't know how else to explain. – Dimitris Maragkos Sep 06 '22 at 11:24
Can you explain `it did not work`? What is it supposed to return and what is it returning instead for you( – Chetan Sep 06 '22 at 12:06

How to get the client's IP automatically in ASP.NET CORE

1 Answers1