How to use a custom HTTP header to get the client remote IP address? #1950

1 Answer(s)

• 

  0

  alper created 2 years ago

  Support Team Director

  Create the below extension class in your web project. Set the ForwardedHeaderName to whatever HTTP header the real IP address is in.

  public static class ApplicationBuilderExtensions
  {
      public static IApplicationBuilder UseCustomHttpHeaders(this IApplicationBuilder builder)
      {
          var options = new ForwardedHeadersOptions
          {
              ForwardedForHeaderName = ForwardedHeadersDefaults.XOriginalHostHeaderName,  //"X-Original-Host"
              ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto
          };
  
          options.KnownNetworks.Clear();
          options.KnownProxies.Clear();
  
          return builder.UseForwardedHeaders(options);
      }
  }
  

  ---

  Open your web module class.

   public override void OnApplicationInitialization(ApplicationInitializationContext context)
  {
      var app = context.GetApplicationBuilder();
      var env = context.GetEnvironment();
  
      if (env.IsDevelopment())
      {
          app.UseDeveloperExceptionPage();
          app.UseCustomHttpHeaders();
      }
      else
      {
          app.UseErrorPage();
          app.UseCustomHttpHeaders();
          app.UseHsts();
  
          app.UseAllElasticApm(context.GetConfiguration());
      }
  
      //...
  

  ---

  Create a simple controller to test it.

  public class Test : Controller
  {
      public string Index()
      {
          return "Client IP Address: " + HttpContext.Connection.RemoteIpAddress.ToString();
      }
  }
  

  ---

  Open Postman and make a GET request to TestController

  PS: If you want to use X-Forwarded-For header, then remove ForwardedForHeaderName = "X-Original-Host" .

  References:

  • https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/proxy-load-balancer
  • https://github.com/IdentityServer/IdentityServer4/blob/main/src/IdentityServer4/src/Endpoints/DiscoveryEndpoint.cs#L53
  • https://github.com/IdentityServer/IdentityServer4/blob/main/src/IdentityServer4/src/Extensions/HttpContextExtensions.cs#L108
  • https://github.com/IdentityServer/IdentityServer4/blob/main/src/IdentityServer4/src/Extensions/HttpContextExtensions.cs#L88

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