diff --git a/README.md b/README.md
index 0007965..c5f2069 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,15 @@ opendkim-key=              # Provided by mail.sh
 ```
 
 ## :: Installation
+Open the following ports:
+
+```
+25
+143
+993
+587
+```
+
 Clone this repo and build it locally or pull it on the registry specified in docker-compose.yaml:
 
 ```