diff --git a/server.js b/server.js
index 1f34b91a3..f8536de2c 100644
--- a/server.js
+++ b/server.js
@@ -41,7 +41,7 @@ import {
 
 import getWebpackServeMiddleware from './src/middleware/webpack-serve.js';
 import basicAuthMiddleware from './src/middleware/basicAuth.js';
-import whitelistMiddleware from './src/middleware/whitelist.js';
+import getWhitelistMiddleware from './src/middleware/whitelist.js';
 import accessLoggerMiddleware, { getAccessLogPath, migrateAccessLog } from './src/middleware/accessLogWriter.js';
 import multerMonkeyPatch from './src/middleware/multerMonkeyPatch.js';
 import initRequestProxy from './src/request-proxy.js';
@@ -125,7 +125,8 @@ if (cliArgs.listen && cliArgs.basicAuthMode) {
 }
 
 if (cliArgs.whitelistMode) {
-    app.use(whitelistMiddleware());
+    const whitelistMiddleware = await getWhitelistMiddleware();
+    app.use(whitelistMiddleware);
 }
 
 if (cliArgs.listen) {
diff --git a/src/middleware/whitelist.js b/src/middleware/whitelist.js
index 9427b3ba8..4cf8d0b79 100644
--- a/src/middleware/whitelist.js
+++ b/src/middleware/whitelist.js
@@ -22,8 +22,6 @@ if (fs.existsSync(whitelistPath)) {
     }
 }
 
-await resolveHostnames();
-
 /**
  * Get the client IP address from the request headers.
  * @param {import('express').Request} req Express request object
@@ -110,9 +108,9 @@ async function resolveHostnames() {
 
 /**
  * Returns a middleware function that checks if the client IP is in the whitelist.
- * @returns {import('express').RequestHandler} The middleware function
+ * @returns {Promise<import('express').RequestHandler>} Promise that resolves to the middleware function
  */
-export default function whitelistMiddleware() {
+export default async function getWhitelistMiddleware() {
     const forbiddenWebpage = Handlebars.compile(
         safeReadFileSync('./public/error/forbidden-by-whitelist.html') ?? '',
     );
@@ -121,6 +119,8 @@ export default function whitelistMiddleware() {
         '/favicon.ico',
     ];
 
+    await resolveHostnames();
+
     return function (req, res, next) {
         const clientIp = getIpFromRequest(req);
         const forwardedIp = getForwardedIp(req);