Check manual page of check_smtp
This is an active check that connects to a SMTP server and checks if the
SMTP protocol works. STARTTLS can be used to establish a SSL encrypted
connection. Using SMTP AUTH is possible.
You can specify a string to expect in the respose of the server. You can
give specific SMTP commands to execute on the connection and define which
responses are expected. Thresholds for the response time can be configured
for WARN and CRIT.
If using SSL you can configure to check for expiration of the SSL certificate
within the next days.
This check can be configured by Wato.
No discovery supported.