diff --git a/content/os/v1.x/en/installation/networking/interfaces/_index.md b/content/os/v1.x/en/installation/networking/interfaces/_index.md
index e3563a5d1a8..535eff0ad97 100644
--- a/content/os/v1.x/en/installation/networking/interfaces/_index.md
+++ b/content/os/v1.x/en/installation/networking/interfaces/_index.md
@@ -26,6 +26,8 @@ rancher:
         dhcp: false
 ```
 
+> **Note:** The `address` item should be the CIDR format.
+
 ### Multiple NICs
 
 If you want to configure one of multiple network interfaces, you can specify the MAC address of the interface you want to configure.