diff --git a/phpBB/includes/session.php b/phpBB/includes/session.php
index 6980277041..84e74a67fb 100644
--- a/phpBB/includes/session.php
+++ b/phpBB/includes/session.php
@@ -1393,7 +1393,7 @@ class session
 		$host = htmlspecialchars($this->host);
 		$ref = substr($this->referer, strpos($this->referer, '://') + 3);
 
-		if (!(stripos($ref, $host) === 0))
+		if (!(stripos($ref, $host) === 0) && (!$config['force_server'] || !(stripos($ref, $config['server_name']) === 0)))
 		{
 			return false;
 		}