Host Reachability Logic

[Envera IT]

Just looking to get some clarification on my setup. I started reading more into the host reachability logic and I'm worried that I've made a design error in my setup.

I'm monitoring ~450 hosts right now with about 350 of them being WAN connections at remote locations. We've got a mixed bag of SNMP capable routers and non SNMP cabable routers. All the non SNMP capable hosts only have host checks applied to them, no service checks. I'm not running any ping service checks as I thought those to be redundant to the host check I'm using (check_icmp). Does not having a service check on a host in anyway impact the host reachability logic? Would it be best for me to have host checks and service checks for all of my hosts?

[Box293]

I'm not running any ping service checks as I thought those to be redundant to the host check I'm using (check_icmp).

Yes you are right, having the ping service checks can be a duplication.

However there are cases where having ping service checks can be useful. The most common case is defining service dependancies (CCM > Advanced > Service Dependancies). You might want to have a couple of services on that host depend on the state of the ping service check. Here is some documentation about host and service dependancies.

Does not having a service check on a host in anyway impact the host reachability logic?

No, there is no impact.

The only areas where it can be a little confusing is when viewing Service Detail (Home -> Service Detail). If a host does not have any services then it will not appear in the list here, only hosts with services do. Here's an example where it can come into play:

• You name your remote sites with a naming standard like 240.1, 240.2, 240.3 etc
  240.1 and 240.2 do not have any services
  240.3 has some SNMP services
  When viewing Service Detail you do a search for 240 so you can see all objects named 240
  However only 240.3 will appear in seach results as it is the only one with services

I hope this has made things clearer.

[Envera IT]

The only areas where it can be a little confusing is when viewing Service Detail (Home -> Service Detail). If a host does not have any services then it will not appear in the list here, only hosts with services do. Here's an example where it can come into play:

I always wondered about that...

Thanks, think I'm good to go.