Doc open ports.

docs/installation-production.md

@@ -183,6 +183,19 @@ Ensure that the Liquidsoap installation path is valid:
 liquidsoap_path="/home/engineuser/.opam/4.08.0/bin/liquidsoap"
 ```
 
+**Configuring the API Server**
+
+Set the correct IP in `/opt/aura/engine/configuration# nano gunicorn.conf.py` and
+the exposed `exposed_api_url` in `engine.ini`.
+
+Also open the `api_port` defined in `engine.ini` in your `iptables` (Default is 3333)
+
+```shell
+iptables -A INPUT -p tcp -m state --state NEW -m tcp --dport 3333 -j ACCEPT
+```
+
+**Configuring the Audio Store**
+
 Finally Engine needs to be able to access the audio folder, where all the tracks of the playlists
 are stored via *Tank*: