diff --git a/Home.md b/Home.md
index 6a10baa..6250190 100644
--- a/Home.md
+++ b/Home.md
@@ -21,6 +21,9 @@ Here is how to turn on the developer mode.<br/>Android -> https://louiszl.gitboo
 IOS go here -> https://github.com/fooxy/homeassistant-aqara/wiki/Enable-dev-mode<br/>
 The password shown in the app must set on the FHEM XioamiSmartHome Gatewaydevice! (see additional pictures below)
 
+# Used Ports
+The gateway communicates via UDP ports 9898 and 4321. If you use a firewall, both ports must be opened. Disabling multicastfilters in your firewall is also a good idea.
+
 # DEFINE
 `define <DEINNAMEWIEDUWILLST> XiaomiSmartHome <IP_DES_MI_GATEWAYS>`