In the net_connect probe, when you configure a host and choose the option to monitor connectivity with Ping, the configured service ports (e.g. telnet, ssh, mnmsrvc, etc) will not be checked if the ping fails. ?Thus, it will not send alarms for the service ports, it will only send the alarm for the Ping failure.
This is configured by default so that the Ping acts like a heartbeat sensor - if the heartbeat fails (i.e. Ping fails) then the other ports are not checked and alarms are not sent for all the service port checks.
There are two options to change this behavior:
1) Disable the Monitor Ping connectivity option in the Host configuration. ?- this disables the Ping check and thus the heartbeat check.
2) Under the General Probe configuration screen, check the box to enable Force Service check - this allows you to keep the Ping connectivity enabled, but it does not affect the service port checks.