Nagios Support Forum

I'm using the evaluation version of Nagios XI (VM appliance) and was initially able to use Auto-Discover without issues. However, auto-discover pointed out some missing DNS entries on my network. Since I prefer to look at hostnames, I added everything missing to DNS and deleted all of my hosts/services that were previously configured through CCM... The idea here was to start fresh, do a new auto-discover scan and use DNS host names in the monitoring wizard.

The problem occurs when I try to re-run auto-discover on the same subnet, I am now getting no results (0 new/0 total). Scanning a single IP results in the same thing... However, I'm able to ping/nmap these IP's just fine when I SSH into Nagios. Am I missing something?

the single IP issue was a bug we discovered and has been fixed in the 2012 RC4
http://www.nagios.com/downloadxi/

To re-discover previously discovered networks you will need to remove previous scans that contain the same addresses

I have removed all hosts, services and scans for these networks and am still coming up with 0 hosts found.

Is this for a single IP?

I just found out that the single IP fix did not make it into RC4

It's for a /24 ideally, but I'm replicating the issue with /32 as well.

Strangely, 2 days ago (before I deleted all the scan/hosts) I was able to auto-discover a single address. I think there has to be some trace of the hosts somewhere, but I've looked through all of the available pages and not seeing any of them. Should I just redeploy the appliance?

Let me ask you, did you add these to your monitoring configuration? Because the Auto-Discovery will not show hosts that are already being monitored..