Update README.MD for opening port for KNX Link Server as well

README.md

@@ -42,13 +42,16 @@ guide you through the installation and asking some questions which you may reply
 
 In nutshell, the steps of [install.sh](./install.sh) script are:
 1. Creating a technical user `knx` for systemd service
-1. Downloading the `knx-link-<version>.jar` file to folder `/opt/knx-link-<version>`
-1. Install `knx.service` to start and keep KNX Link server running (e.g. after reboot)
-1. (Optional) Create a `knx` firewall rule for your `firewalld`, which opens the UDP port `3671` which is 
-   registered for KNX communication. Opens UDP ports `40001` (for Description Channel), `40002` 
-   (for Control Channel) and `40003` (for Data Channel) which are required for communication without NAT.
-1. Check if the systemd service is running 
-1. (Optional) Check if the port of KNX Link server is open
+2. Downloading the `knx-link-<version>.jar` file to folder `/opt/knx-link-<version>`
+3. Install `knx.service` to start and keep KNX Link server running (e.g. after reboot)
+4. (Optional) Create a `knx` firewall rule for your `firewalld`, which opens some ports for KNX communication:
+   1. TCP port `3672` for KNX Link server itself to listen incoming requests
+   2. UDP port `3671` for KNX communication
+   3. UDP port `40001` for Description Channel (required for NAT communication)
+   4. UDP port `40002` for Control Channel (required for NAT communication)
+   5. UDP port `40003` for Data Channel (required for NAT communication)
+5. Check if the systemd service is running 
+6. (Optional) Check if the port of KNX Link server is open
 
 #### How to start, stop or restart KNX Link Server?