diff --git a/README.md b/README.md
index 9383fbc..eef5143 100755
--- a/README.md
+++ b/README.md
@@ -173,12 +173,14 @@ You can copy an example of server file from here: `/examples/nginx/server.conf`
 Edit the file `/etc/nginx/mime.types`<br>
 `application/javascript js;` -> `application/javascript js mjs;`
 
-3. Generate a TLS/SSL sertificate (via [certbot](http://certbot.eff.org/))<br>
-3.1. `sudo apt-get install software-properties-common`<br>
-3.2. `sudo add-apt-repository ppa:certbot/certbot`<br>
-3.3. `sudo apt-get update`<br>
-3.4. `sudo apt install certbot python-certbot-nginx`<br>
-3.5. `sudo certbot certonly --nginx`
+3. **Generate a TLS/SSL sertificate** (via [certbot](http://certbot.eff.org/) for [ubuntu](https://ubuntu.com/))<br>
+3.1. `sudo apt install certbot python3-certbot-nginx`<br>
+3.2. `sudo certbot certonly --nginx` (The **domain** must already be **bound** to the **IP-address** of the server by `A-record` or `AAAA-record`)
+
+5. **Firewall rules for HTTP and HTTPS** (for [ubuntu](https://ubuntu.com/))<br>
+4.1 `sudo ufw allow "NGINX Full"`<br>
+4.1.1 `sudo ufw allow 22` (make sure that the port for SSH connection is open)<br>
+4.2 `sudo ufw enable`
 
 ### SystemD (or any alternative you like)
 You can copy an example of systemd file from here: `/examples/systemd/huesos.service`<br>
@@ -189,7 +191,6 @@ You can copy an example of systemd file from here: `/examples/systemd/huesos.ser
 *before you execute the command think about **what it does** and whether the **paths** are specified correctly*<br>
 *the configuration file is very simple and you can remake it for any alternative to SystemD that you like*
 
-
 ## Menu
 *Menu inside the Web App*<br><br>
 Make sure you have a **menu** collection (can be created automatically)<br>