diff --git a/Classes/Command/SetupCommandController.php b/Classes/Command/SetupCommandController.php
index 89b3535..32ecb83 100644
--- a/Classes/Command/SetupCommandController.php
+++ b/Classes/Command/SetupCommandController.php
@@ -20,11 +20,11 @@
 use Neos\Setup\Domain\CliEnvironment;
 use Neos\Setup\Domain\HealthcheckEnvironment;
 use Neos\Setup\Infrastructure\HealthChecker;
-use Neos\Setup\RequestHandler\SetupCliRequestHandler;
 use Neos\Utility\Arrays;
 use Neos\Setup\Exception as SetupException;
 use Neos\Setup\Infrastructure\Database\DatabaseConnectionService;
 use Symfony\Component\Yaml\Yaml;
+use Neos\Utility\Files;
 
 class SetupCommandController extends CommandController
 {
@@ -185,6 +185,7 @@ private function writeSettings(string $filename, string $path, $settings): strin
             $previousSettings = [];
         }
         $newSettings = Arrays::setValueByPath($previousSettings, $path, $settings);
+        Files::createDirectoryRecursively(dirname($filename));
         file_put_contents($filename, YAML::dump($newSettings, 10, 2));
         return YAML::dump(Arrays::setValueByPath([], $path, $settings), 10, 2);
     }
diff --git a/Classes/Infrastructure/Healthcheck/TrustedProxiesHealthcheck.php b/Classes/Infrastructure/Healthcheck/TrustedProxiesHealthcheck.php
new file mode 100644
index 0000000..7138500
--- /dev/null
+++ b/Classes/Infrastructure/Healthcheck/TrustedProxiesHealthcheck.php
@@ -0,0 +1,224 @@
+<?php
+
+namespace Neos\Setup\Infrastructure\Healthcheck;
+
+use Neos\Flow\Configuration\ConfigurationManager;
+use Neos\Flow\Utility\Ip as IpUtility;
+use Neos\Setup\Domain\Health;
+use Neos\Setup\Domain\HealthcheckEnvironment;
+use Neos\Setup\Domain\HealthcheckInterface;
+use Neos\Setup\Domain\Status;
+use Neos\Setup\Domain\WebEnvironment;
+
+class TrustedProxiesHealthcheck implements HealthcheckInterface
+{
+    /**
+     * Centralized list of reverse proxy headers with their configuration mapping categories
+     * Header name => mappingKey (clientIp, host, port, proto) or null for detection-only headers
+     * Priority is determined by array order for headers with the same mappingKey
+     */
+    private const REVERSE_PROXY_HEADERS = [
+        // Standard reverse proxy headers with mapping
+        'X-Forwarded-For' => 'clientIp',
+        'X-Forwarded-Host' => 'host',
+        'X-Forwarded-Port' => 'port',
+        'X-Forwarded-Proto' => 'proto',
+        'X-Real-IP' => 'clientIp',
+        'Forwarded' => null, // RFC 7239 - detection only
+
+        // Additional clientIp headers (priority order)
+        'True-Client-IP' => 'clientIp',
+        'X-Client-IP' => 'clientIp',
+        'Client-IP' => 'clientIp',
+
+        // Cloudflare
+        'CF-Connecting-IP' => 'clientIp',
+        'CF-Visitor' => null,
+        'CF-RAY' => null,
+        'CF-IPCountry' => null,
+
+        // AWS
+        'X-Amzn-Trace-Id' => null,
+        'X-Amz-Cf-Id' => null,
+        'CloudFront-Viewer-Address' => 'clientIp',
+
+        // Google Cloud
+        'X-Cloud-Trace-Context' => null,
+
+        // Azure
+        'X-Azure-ClientIP' => 'clientIp',
+        'X-ARR-ClientIP' => 'clientIp',
+
+        // Fastly / Other CDNs
+        'Fastly-Client-IP' => 'clientIp',
+        'X-Forwarded-Ssl' => null,
+        'X-Original-Forwarded-For' => 'clientIp',
+        'X-Original-Host' => 'host',
+    ];
+
+    public function __construct(
+        private ConfigurationManager $configurationManager,
+    ) {
+    }
+
+    public function getTitle(): string
+    {
+        return 'Trusted Proxies Configuration';
+    }
+
+    public function execute(HealthcheckEnvironment $environment): Health
+    {
+        if ($environment->executionEnvironment instanceof WebEnvironment) {
+            $trustedProxiesConfig = $this->configurationManager->getConfiguration(ConfigurationManager::CONFIGURATION_TYPE_SETTINGS, 'Neos.Flow.http.trustedProxies');
+            $configuredHeaders = $trustedProxiesConfig['headers'] ?? [];
+            $configuredProxies = $trustedProxiesConfig['proxies'] ?? [];
+
+            if (is_string($configuredProxies)) {
+                $configuredProxies = array_map('trim', explode(',', $configuredProxies));
+            }
+
+            $remoteAddr = $_SERVER['REMOTE_ADDR'] ?? null;
+
+            // Check if any reverse proxy header is present
+            $detectedProxyHeaders = [];
+            foreach (self::REVERSE_PROXY_HEADERS as $header => $mappingKey) {
+                if (isset($_SERVER['HTTP_' . strtoupper(str_replace('-', '_', $header))])) {
+                    $detectedProxyHeaders[] = $header;
+                }
+            }
+
+            if (count($detectedProxyHeaders) > 0) {
+                $message = "Reverse proxy headers detected: " . implode(', ', $detectedProxyHeaders) . "<br /><br />";
+            } else {
+                $message = "No reverse proxy headers detected.<br /><br />";
+            }
+
+
+            if (!empty($detectedProxyHeaders)) {
+                // Reverse proxy headers detected
+                // -> config is OK ($isRemoteAddrTrusted==true) if the current REMOTE_ADDR matches any configured trusted proxy
+                $isProxyConfigured = !empty($configuredProxies);
+                $isRemoteAddrTrusted = false;
+
+                if ($isProxyConfigured && $remoteAddr) {
+                    $isRemoteAddrTrusted = self::matchesProxyPattern($remoteAddr, $configuredProxies);
+                }
+
+                if (!$isProxyConfigured || !$isRemoteAddrTrusted) {
+                    // Trusted proxies not configured or don't match REMOTE_ADDR
+
+                    if (!$isProxyConfigured) {
+                        $message .= "<b>Trusted proxies are not configured.</b> ";
+                    } else {
+                        $message .= "The current REMOTE_ADDR {$remoteAddr} does not match any configured trusted proxies "  . implode(',', $configuredProxies) . ". ";
+                    }
+
+                    $message .= "You need to configure trusted proxies to ensure URLs can be properly built.<br /><br />";
+                    $message .= "Configure via Settings.yaml:<br /><br />";
+                    $message .= "<pre>Neos:\n";
+                    $message .= "  Flow:\n";
+                    $message .= "    http:\n";
+                    $message .= "      trustedProxies:\n";
+
+                    if ($remoteAddr) {
+                        $message .= "        proxies: ['{$remoteAddr}']\n";
+                    } else {
+                        $message .= "        proxies: ['<your-proxy-ip>']\n";
+                    }
+
+                    // Generate headers configuration mapping based on detected headers
+                    $headersMapping = self::generateHeadersMapping($detectedProxyHeaders);
+                    if (!empty($headersMapping)) {
+                        $message .= "        headers:\n";
+                        foreach ($headersMapping as $key => $header) {
+                            $message .= "          {$key}: '{$header}'\n";
+                        }
+                    }
+
+                    $message .= "    </pre>\n";
+
+
+                    $message .= "Alternatively, set the FLOW_HTTP_TRUSTED_PROXIES={$remoteAddr} environment variable.<br />";
+                    $message .= 'See <a href="https://flowframework.readthedocs.io/en/stable/TheDefinitiveGuide/PartIII/Http.html#trusted-proxies">Documentation on trusted proxies</a> for further details.';
+
+                    return new Health($message, Status::WARNING());
+                } else {
+                    // Trusted proxies properly configured
+                    return new Health(
+                        "Reverse proxy configuration appears correct.<br />" .
+                        "Detected headers: " . implode(', ', $detectedProxyHeaders) . "<br />" .
+                        "REMOTE_ADDR ({$remoteAddr}) is configured as a trusted proxy.",
+                        Status::OK()
+                    );
+                }
+            } else {
+                // No reverse proxy headers detected
+                if (!empty($configuredProxies)) {
+                    return new Health(
+                        "No reverse proxy headers detected in the request, but trusted proxies are configured.<br /><br />" .
+                        "If you are not running behind a reverse proxy, you should remove the trusted proxies configuration in Settings.yaml, path Neos.Flow.http.trustedProxies.proxies; and remove the environment variable FLOW_HTTP_TRUSTED_PROXIES.<br />" .
+                        "Otherwise, ensure your reverse proxy is properly configured to send the expected headers.",
+                        Status::WARNING()
+                    );
+                } else {
+                    return new Health(
+                        "No reverse proxy headers detected. Running in direct connection mode.<br />" .
+                        "Trusted proxies configuration is not set, which is correct for this setup.",
+                        Status::OK()
+                    );
+                }
+            }
+        }
+
+        // Fallback for CLI environment
+        return new Health(
+            <<<'MSG'
+                If you are behind a reverse proxy, you need to configure trusted proxies, to ensure URLs can be
+                properly built. This is possible via Settings.yaml at Neos.Flow.http.trustedProxies,
+                or the FLOW_HTTP_TRUSTED_PROXIES environment variable.
+
+                See https://flowframework.readthedocs.io/en/stable/TheDefinitiveGuide/PartIII/Http.html#trusted-proxies
+                for further details.
+
+                You can also run the web-based setup wizard at /setup, which checks if trusted proxies are set up correctly.
+                MSG,
+            Status::UNKNOWN()
+        );
+    }
+
+    private static function matchesProxyPattern(string $remoteAddr, array $configuredProxies): bool
+    {
+        foreach ($configuredProxies as $ipPattern) {
+            if ($ipPattern === '*') {
+                return true;
+            }
+            if (IpUtility::cidrMatch($remoteAddr, $ipPattern)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Generate headers Neos config mapping based on detected headers
+     */
+    private static function generateHeadersMapping(array $detectedHeaders): array
+    {
+        $mapping = [];
+
+        // Process headers in priority order (as defined in REVERSE_PROXY_HEADERS)
+        // First match wins for each mappingKey
+        foreach (self::REVERSE_PROXY_HEADERS as $header => $mappingKey) {
+            // Skip headers without a mapping key (detection only) or already mapped keys (as these then have higher priorities)
+            if ($mappingKey === null || isset($mapping[$mappingKey])) {
+                continue;
+            }
+
+            if (in_array($header, $detectedHeaders, true)) {
+                $mapping[$mappingKey] = $header;
+            }
+        }
+
+        return $mapping;
+    }
+}
diff --git a/Configuration/Settings.yaml b/Configuration/Settings.yaml
index 82559dd..f9bf1bf 100644
--- a/Configuration/Settings.yaml
+++ b/Configuration/Settings.yaml
@@ -16,6 +16,9 @@ Neos:
         doctrine:
           position: 'start 100'
           className: Neos\Setup\Infrastructure\Healthcheck\DoctrineHealthcheck
+        trustedProxies:
+          position: 'start 50'
+          className: Neos\Setup\Infrastructure\Healthcheck\TrustedProxiesHealthcheck
 
     #
     # The database drivers that are supported by migrations