diff --git a/deployhooks.md b/deployhooks.md
index 071b031..2fe4b08 100644
--- a/deployhooks.md
+++ b/deployhooks.md
@@ -534,6 +534,7 @@ deploy script to work.
 ```sh
 export ROUTER_OS_USERNAME=certuser
 export ROUTER_OS_HOST=router.example.com
+export ROUTER_OS_PORT=22
 
 acme.sh --deploy -d ftp.example.com --deploy-hook routeros
 ```