diff --git a/docs/prerequisite-system.md b/docs/prerequisite-system.md
index ecf6dbf96..9cefa6697 100644
--- a/docs/prerequisite-system.md
+++ b/docs/prerequisite-system.md
@@ -44,9 +44,9 @@ We can help to correctly plan your setup as part of our support.
 Please check if any of mailcow's standard ports are open and not in use by other applications:
 
 ```
-ss -tlpn | grep -E -w '25|80|110|143|443|465|587|993|995|4190'
+ss -tlpn | grep -E -w '25|80|110|143|443|465|587|993|995|4190|5222|5269'
 # or:
-netstat -tulpn | grep -E -w '25|80|110|143|443|465|587|993|995|4190'
+netstat -tulpn | grep -E -w '25|80|110|143|443|465|587|993|995|4190|5222|5269'
 ```
 
 !!! warning