diff --git a/lib/private/RedisFactory.php b/lib/private/RedisFactory.php
index 754437c06c..22d02e07c2 100644
--- a/lib/private/RedisFactory.php
+++ b/lib/private/RedisFactory.php
@@ -72,8 +72,10 @@ class RedisFactory {
 			}
 			if (isset($config['port'])) {
 				$port = $config['port'];
-			} else {
+			} else if ($host[0] !== '/') {
 				$port = 6379;
+			} else {
+				$port = null;
 			}
 			if (isset($config['timeout'])) {
 				$timeout = $config['timeout'];