diff --git a/core/admin/mailu/internal/__init__.py b/core/admin/mailu/internal/__init__.py
index 9e8c3690..45084fe5 100644
--- a/core/admin/mailu/internal/__init__.py
+++ b/core/admin/mailu/internal/__init__.py
@@ -1,6 +1,19 @@
-from flask import Blueprint
+from mailu import limiter
+
+import socket
+import flask
 
 
-internal = Blueprint('internal', __name__)
+internal = flask.Blueprint('internal', __name__)
+
+
+@limiter.request_filter
+def whitelist_webmail():
+    try:
+        return flask.request.headers["Client-Ip"] ==\
+            socket.gethostbyname("webmail")
+    except:
+        return False
+
 
 from mailu.internal import views