What is NagMon?
NagMon is an iPhone and iPad client for Nagios Core. It gives you an alternative interface to the Nagios web UI, tailored to iOS: a fast, at-a-glance dashboard, live host and service status, filtering and sorting built for a phone screen, and the ability to acknowledge problems or schedule downtime on the go. It talks directly to your own Nagios server — there is no middleman service, and nothing about your infrastructure ever leaves your device.
To use NagMon with a real server, you need:
- A Nagios Core 4.x server with the JSON CGIs available (
statusjson.cgiand, for host groups,objectjson.cgi). These ship with Nagios Core 4 by default. - A network path from your device to that server — same network, VPN, or a securely published web interface (see Secure Remote Access to Your Nagios Server).
- A Nagios web-interface account (the same username and password you use in the browser).
Trying the app without a server
You don't need a Nagios server to explore NagMon. The app ships with a built-in Demo Server — a simulated small Nagios installation with hosts and services in mixed states: up, down, warning, critical, acknowledged, in scheduled downtime, and pending. Timestamps are generated relative to the current time, so the demo always looks live.
You can switch to the Demo Server directly from onboarding, before entering any server details. It's the quickest way to get a feel for the dashboard, the list views, and the detail screens — and a handy sanity check later: if the demo works but your server doesn't, the problem is connectivity or configuration, not the app.
Connecting your first server
The onboarding form asks for five things:
| Field | What to enter |
|---|---|
| Hostname | The DNS name or IP address of your Nagios server, e.g. nagios.example.com or 192.168.1.50. No http:// prefix needed. |
| Port | Leave at the default unless your web server listens on a custom port (e.g. 8443). |
| Path | The base path of your Nagios web interface — usually just nagios. Do not include cgi-bin, status.cgi, or any page name. |
| Username | Your Nagios web-interface user, e.g. nagiosadmin. |
| Password | The matching password. Credentials are stored only on your device. |
https://nagios.example.com/nagios/ in a browser, the path is nagios — nothing more. NagMon builds the full CGI URLs (like /nagios/cgi-bin/statusjson.cgi) itself.
HTTP vs. HTTPS
NagMon connects over HTTPS or plain HTTP. If your server only offers HTTP, the app will warn you: an unencrypted connection sends your Nagios credentials in a form that anyone on the network path can read. HTTP is tolerable on a trusted LAN or over a VPN, but if the server is reachable across the internet, set up HTTPS first — our remote access guide walks through it with Let's Encrypt.
Verifying the connection
Once you save the server, NagMon fetches live status and the Dashboard fills in. If the connection fails, the most common causes are a path field containing more than the base path, a hostname your phone can't resolve, or an HTTPS/port mismatch. The Troubleshooting guide has a step-by-step checklist, including a browser test you can run in ten seconds.
A quick tour of the tabs
- Dashboard — the landing tab: host and service state counts, current problems prioritized, and per-server connection warnings. Details →
- Hosts — every monitored host with status filters, sorting, and optional grouping by host group. Details →
- Services — every service check, filterable by OK, Warning, Critical, Unknown, or Pending. Details →
- Alerts — the server's recent event history, sortable by time, severity, or host. Details →
- Settings — servers, appearance, language, and support. Details →
Don't have NagMon yet?
Free on the App Store. No ads, no analytics, no tracking — your monitoring data stays on your device.