feat: update doc/certbot.md

doc/certbot.md

@@ -25,3 +25,48 @@ sudo snap install --classic certbot
 ```
 sudo ln -s /snap/bin/certbot /usr/bin/certbot
 ```
+
+* OPTION: set up virtual host [this](./apache-vh.md)
+
+* check, open the virtual host file for your domain
+```
+sudo vi /etc/apache2/sites-available/vm2037.swingbe.mooo.com.conf
+```
+
+* verify the syntax of your configuration edits
+```
+sudo apache2ctl configtest
+```
+
+* verify the current firewall setting by running
+```
+sudo ufw status
+```
+
+* allow HTTPS traffic, allow the “WWW Full” profile and delete the redundant “WWW” profile allowance
+```
+sudo ufw allow 'WWW Full'
+sudo ufw delete allow 'WWW'
+sudo ufw status
+```
+
+* Certbot provides a variety of ways to obtain SSL certificates through plugins. The Apache plugin will take care of reconfiguring Apache and reloading the configuration whenever necessary. To use this plugin, run the following
+```
+sudo certbot --apache -d vm2037.swingbe.mooo.com
+```
+
+* Let’s Encrypt certificates are only valid for ninety days. This is to encourage users to automate their certificate renewal process. The certbot package you installed takes care of this for you by adding a renew script to /etc/cron.d. This script runs twice a day and will automatically renew any certificate that’s within thirty days of expiration. To test the renewal process, you can do a dry run with certbot
+```
+sudo certbot renew --dry-run
+```
+
+* test manual renewal
+```
+sudo /usr/bin/certbot renew --apache --quiet
+```
+
+//TODO Enable `MAILTO`!
+* extend `crontab -e` for auto renewal with this content
+```
+@daily /usr/bin/certbot renew --apache --quiet
+```