How to check my sql database status

 https://linuxhint.com/check-mysql-status-ubuntu/

How To Configure Firewall with UFW on Ubuntu 20.04 LTS

 https://www.cyberciti.biz/faq/how-to-configure-firewall-with-ufw-on-ubuntu-20-04-lts/

Port Forwarding Tester

 

https://www.yougetsignal.com/tools/open-ports/

List of TCP and UDP port numbers

 

https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

Error: Unable to load CA certificates on Mosquitto Broker Server

1637245173: Error: Unable to load CA certificates. Check cafile "/etc/letsencrypt/live/10.0.36.50/chain.pem".

1637245173: Error: Unable to load server certificate "/etc/letsencrypt/live/10.0.36.50/cert.pem". Check certfile.

1637245173: OpenSSL Error[0]: error:02001002:system library:fopen:No such file or directory

1637245173: OpenSSL Error[1]: error:20074002:BIO routines:file_ctrl:system lib

1637245173: OpenSSL Error[2]: error:140DC002:SSL routines:use_certificate_chain_file:system lib

Mosquitto man page

 https://mosquitto.org/man/mosquitto-8.html

MQTT broker

 1. https://www.emqx.io/

2. https://www.hivemq.com/

3, https://mosquitto.org/

Node-RED

 https://nodered.org/

The open port checker is a tool you can use to check your external IP address and detect open ports on your connection

 

https://www.yougetsignal.com/tools/open-ports/

Install Mosquitto MQTT Broker On Ubuntu 20.04 Server

 https://www.digitalocean.com/community/tutorials/how-to-install-and-secure-the-mosquitto-mqtt-messaging-broker-on-ubuntu-16-04

Explain Shell

 https://explainshell.com/explain/8/netstat

How To Install Nginx on Ubuntu 20.04

 https://www.digitalocean.com/community/tutorials/how-to-install-nginx-on-ubuntu-20-04

Ubuntu Nginx SSL: How to install an SSL certificate on Ubuntu for Nginx

 https://www.godaddy.com/garage/how-to-install-an-ssl-certificate-on-ubuntu-for-nginx/

SSL on Nginx throws error (SSL: error:0908F066:PEM routines:get_header_and_data:bad end line)

 https://stackoverflow.com/questions/62514704/ssl-on-nginx-throws-error-ssl-error0908f066pem-routinesget-header-and-data

nginx.service failed because the control process exited

 https://stackoverflow.com/questions/35868976/nginx-service-failed-because-the-control-process-exited/58332311#58332311

Extracting the certificate and keys from a .pfx file

 https://www.ibm.com/docs/en/arl/9.7?topic=certification-extracting-certificate-keys-from-pfx-file

COMODO SSL Certificate Installation: Nginx

 https://techglimpse.com/comodo-ssl-certificate-installation-nginx/

Secure Nginx with Let's Encrypt on Ubuntu 20.04

 https://linuxize.com/post/secure-nginx-with-let-s-encrypt-on-ubuntu-20-04/

https://www.webfoobar.com/node/146