Add forwarded headers

Source/ProofOfConcept/Program.cs

@@ -39,6 +39,20 @@ builder.Services.AddHttpClient().AddHttpClient("InsecureClient")
             HttpClientHandler.DangerousAcceptAnyServerCertificateValidator
     });
 
+// If you know your proxy IP(s), specify them for security.
+builder.Services.Configure<ForwardedHeadersOptions>(options =>
+{
+    options.ForwardedHeaders =
+        ForwardedHeaders.XForwardedFor |
+        ForwardedHeaders.XForwardedProto |
+        ForwardedHeaders.XForwardedHost;
+
+    // Trust specific proxy or network:
+    options.KnownProxies.Clear();
+    options.KnownNetworks.Clear();
+    options.ForwardLimit = null; // but prefer being explicit when possible
+});
+
 builder.Services
     .AddAuthentication(o =>
     {