diff --git a/iplookup/index.php b/iplookup/index.php
index e26f72caada..07981ed169d 100644
--- a/iplookup/index.php
+++ b/iplookup/index.php
@@ -27,7 +27,11 @@
 require('../config.php');
 require_once('lib.php');
 
-require_login();
+require_login(0, false);
+if (isguestuser()) {
+    // Guest users cannot perform lookups.
+    throw new require_login_exception('Guests are not allowed here.');
+}
 
 $ip   = optional_param('ip', getremoteaddr(), PARAM_HOST);
 $user = optional_param('user', 0, PARAM_INT);