diff --git a/engine/userguide/networking/default_network/custom-docker0.md b/engine/userguide/networking/default_network/custom-docker0.md
index b1dfb88083..3c28cbb16f 100644
--- a/engine/userguide/networking/default_network/custom-docker0.md
+++ b/engine/userguide/networking/default_network/custom-docker0.md
@@ -36,7 +36,7 @@ following settings to configure the default bridge network:
   "bip": "192.168.1.5/24",
   "fixed-cidr": "10.20.0.0/16",
   "fixed-cidr-v6": "2001:db8::/64",
-  "mtu": "1500",
+  "mtu": 1500,
   "default-gateway": "10.20.1.1",
   "default-gateway-v6": "2001:db8:abcd::89",
   "dns": ["10.20.1.2","10.20.1.3"]