Nagios Host vs Service?

[nagionoob]

Hello everyone,

I have a question about host vs service. I know that a host is like the physical machine, and services are the items running on the host, like http, ftp etc. However, we have card readers on our network that we are monitoring. Under the host definition, we are using check-host-alive. Since they are just card readers, they are "dumb" and really can only respond to ping. They have no ability to run a service, nor would any service be associated with them. However, in Nagios, it shows that there is a ping service on them. Here is a screenshot of what I am talking about.



In the config files, each host is running the check-host-alive command, while the service section is running a check-ping command. Basically, what I am wondering is, what is the difference between a host and a service in nagios, and if running check-host-alive, and check-ping is redundant, and should I only run the check-host alive command?

Thanks for your time!

[slansing]

A Host is a central device from which services are monitored. This could be anything from Windows Event log's to Drive space under a Windows server, to which ports are being used on a Switch. What you are seeing is the ping check that is automatically applied to nearly every Host. The Host-Alive-Check is in essence a ping check, so it is really showing the same thing.