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Two Nagios Servers - Inside / Outside Firewall

Posted: Tue Oct 28, 2025 12:29 pm
Hi,
I'm new to NagiosXI and looking for a solution to what I hope is a typical problem. We have dozens of servers with public access and private non-public servers. We have a fully implemented NagiosXI instance behind our firewall working as needed.

Our problem concerns the public facing sites which rely on 3rd party monitors and it is getting costly. Our current assumption is we would like to have an "internal NagiosXI " and "external NagiosXI " to test same sites for each 'location'

I believe with our existing setup we would never know if our site/servers we not available to the public. I would like minimize the duplication of efforts from adding monitors to both hosts. Maybe a master/slave situation where the setup is shared or replicated?

Any help or suggestions for simplified internal and external monitoring would be appreciated!

Thanks,
Will

Re: Two Nagios Servers - Inside / Outside Firewall

Posted: Tue Oct 28, 2025 1:21 pm
by DoubleDoubleA
Hi Will,

I suppose you could add another XI. I'm not sure that's necessary, but sales would totally sell you another license.

Is your primary concern logical separation between inside and outside? Or are there network/firewall concerns about getting to or from the "external" servers to Nagios XI? Or is it that you want a totally "external XI" to test your public availability?

If it is the last one, you could look into Nagios Mod-Gearman. Leveraging a Nagios Mod-Gearman worker externally, like on a cloud VM external to your main network, would allow you to run checks "externally" to ensure your public-facing sites were accessible. If you had a Nagios hostgroup that was just the public-facing sites, you could send just the checks for that hostgroup to the Nagios Mod-Gearman worker. You would need to ensure that the worker can get through your firewall to your Nagios XI to return the check results.

https://www.nagios.org/projects/nagios-mod-gearman/