Simple Zabbix script and template for checking validity and expiration of TLS/SSL certificate for given host and port. Adapted from selivan/https-ssl-cert-check-zabbix

Installation on Zabbix server

• Copy ssl_cert_check.sh to /usr/lib/zabbix/externalscripts
• Change ownership and set permissions

cd /usr/lib/zabbix/externalscripts
chmod 755 ssl_cert_check.sh
chown zabbix:zabbix ssl_cert_check.sh

• Import template_zabbix_ssl_checks.xml into Zabbiz templates via the Zabbix UI.
• Assign the template to your hosts that you want to monitor
• Ensure you have a valid entry in each hosts "DNS" field, otherwise it'll fail to run the SSL checks.

The default port 443 will be used to connect and check the SSL certificate. If you use a different port for a specific host, then do this:

• Ggo to the Macros tab on your host in Zabbix
• Click "Inherited and host macros"
• Press the "Change" link next to that macro.
• Change the value for {$SSL_PORT} from 443 to your desired port
• Press Update button at the bottom of your Macros page.