Simple Question, UNREACHABLE vs DOWN

[Steven Coutts]

On Thursday 29 September 2005 15:55, Pete Dewell wrote:
> Fair point.
> Are all the switches on the same subnet mask, and accessible directly
> from the Nagios server? If this is the case, then Nagios can still reach
> the hosts that maybe *should* be marked as unreachable, so will check
> the hosts directly.
>
> I was thinking more of (as in my case) a router with hosts behind it on
> a different network - no direct connection from Nagios to the
> unreachable host(s) *except* through the parent.
>
> Pete Dewell.
>
> Steven Coutts wrote:
> >> Unreachable is when the parent of a host is down. e.g. if host1 is
> >> down, then any hosts that have host1 as a parent will be marked as
> >> unreachable, since Nagios cannot connect to those hosts to check them.
> >>
> >> Pete Dewell
> >
> > Ah I see, pretty obvious really!
> >
> > Makes sense from my stats, expect one anomaly. One of my switches went
> > down, this switch has three other switches hanging off it (all three
> > have the correct parent set in my config) but only two have been marked
> > as being unreachable for that period!!
> >
> > Thanks

The switches are being monitored on a completely different vlan/subnet to what 
the Nagios server is sitting on. There is no possible way it could have 
contacted this switch when it's parent went down.

Double checked the parent directive and it is set correctly. I will test this 
when I can, but my network is such that any downtime for any part of it 
results in a complete bollocking!!

Regards

-- 
Steven Coutts B.Sc.(Hons) MBCS
scoutts at bcs.org.uk

PGP Public Key
http://stevec.couttsnet.com/scoutts.asc
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