--- a/OrthancFramework/Sources/HttpServer/HttpServer.cpp	Fri Jul 04 15:33:46 2025 +0200
+++ b/OrthancFramework/Sources/HttpServer/HttpServer.cpp	Mon Jul 07 16:30:11 2025 +0200
@@ -1203,15 +1203,6 @@
     
     AccessMode accessMode = IsAccessGranted(server, headers);
 
-    // Authenticate this connection
-    if (server.IsAuthenticationEnabled() && 
-        accessMode == AccessMode_Forbidden)
-    {
-      output.SendUnauthorized(server.GetRealm());   // 401 error
-      return;
-    }
-
-    
 #if ORTHANC_ENABLE_MONGOOSE == 1
     // Apply the filter, if it is installed
     char remoteIp[24];
@@ -1248,6 +1239,41 @@
     }
 
 
+    // Authenticate this connection
+    if (server.IsAuthenticationEnabled() &&
+        accessMode == AccessMode_Forbidden)
+    {
+      if (server.IsRedirectForbiddenToRoot() &&
+          uri.size() > 0)
+      {
+        // This is new in Orthanc 1.12.9
+        std::string redirectionToRoot;
+
+        std::string tmp(requestUri);
+        if (tmp.back() == '/')
+        {
+          redirectionToRoot = "../";
+        }
+        else
+        {
+          redirectionToRoot = "./";
+        }
+
+        for (size_t i = 0; i < uri.size() - 1; i++)
+        {
+          redirectionToRoot += "../";
+        }
+
+        output.Redirect(redirectionToRoot);
+      }
+      else
+      {
+        output.SendUnauthorized(server.GetRealm());   // 401 error
+      }
+      return;
+    }
+
+
     // Compute the HTTP method, taking method faking into consideration
     method = HttpMethod_Get;
 
@@ -2204,4 +2230,17 @@
     }
   }
 #endif
+
+
+  bool HttpServer::IsRedirectForbiddenToRoot() const
+  {
+    return redirectForbiddenToRoot_;
+  }
+
+
+  void HttpServer::SetRedirectForbiddenToRoot(bool redirect)
+  {
+    Stop();
+    redirectForbiddenToRoot_ = redirect;
+  }
 }

--- a/OrthancFramework/Sources/HttpServer/HttpServer.h	Fri Jul 04 15:33:46 2025 +0200
+++ b/OrthancFramework/Sources/HttpServer/HttpServer.h	Mon Jul 07 16:30:11 2025 +0200
@@ -114,6 +114,7 @@
     unsigned int threadsCount_;
     bool tcpNoDelay_;
     unsigned int requestTimeout_;  // In seconds
+    bool redirectForbiddenToRoot_;  // New in Orthanc 1.12.9
 
 #if ORTHANC_ENABLE_PUGIXML == 1
     WebDavBuckets webDavBuckets_;
@@ -226,5 +227,9 @@
                                   const std::map<std::string, std::string>& headers,
                                   const std::string& body,
                                   const std::string& boundary);
+
+    bool IsRedirectForbiddenToRoot() const;
+
+    void SetRedirectForbiddenToRoot(bool redirect);
   };
 }