Raspberry Pi Network Monitor: Nagios & Grafana Setup

A Raspberry Pi network monitor running Nagios and Grafana gives you real-time visibility into your home or office network — tracking bandwidth usage, device availability, latency, and service health. This is the same monitoring stack used by enterprise IT teams, running on hardware that costs less than a single month of commercial monitoring subscriptions.

Why Monitor Your Network
Hardware Requirements
The Monitoring Stack
Setting Up Nagios Core
InfluxDB and Grafana Dashboard
Configuring Alerts and Notifications
What to Monitor on an Indian Network
Frequently Asked Questions
Conclusion

Why Monitor Your Network

Without monitoring, you discover network problems when users complain. With a Pi-based monitoring system, you detect issues before they affect anyone:

ISP performance tracking: Log actual download/upload speeds from your Indian ISP (JioFiber, Airtel, ACT) and identify when they underperform
Device availability: Know instantly when a NAS, printer, access point, or smart home device goes offline
Bandwidth monitoring: Identify which devices consume the most bandwidth
Latency tracking: Monitor ping times to critical services (your office VPN, cloud servers, gaming servers)
Historical data: Prove to your ISP that speeds dropped during specific hours with timestamped evidence

🛒 Recommended: Raspberry Pi 5 4GB RAM — Runs Nagios, InfluxDB, and Grafana comfortably for a home or small office network monitoring setup.

Hardware Requirements

Raspberry Pi 5 (4GB sufficient for monitoring 20-50 devices)
MicroSD card (32GB) or NVMe SSD (recommended for database writes)
Ethernet cable (wired connection is essential for accurate network measurements)
USB-C power supply (5V/5A)
Case with cooling

Always connect the monitoring Pi via Ethernet, not Wi-Fi. Wi-Fi introduces variable latency that corrupts your monitoring data — you need the Pi to have a stable, low-latency connection to measure everything else accurately.

The Monitoring Stack

The recommended stack uses three components, each handling a different aspect:

Nagios Core: Active monitoring — pings devices, checks service ports, sends alerts when things go down
InfluxDB: Time-series database — stores historical metrics (bandwidth, latency, temperature) efficiently
Grafana: Visualisation — creates dashboards with graphs, gauges, and tables from InfluxDB data

For simpler setups, you can use Prometheus instead of InfluxDB, or skip Nagios and use only Grafana with data collectors. But the full stack provides the most comprehensive monitoring.

Setting Up Nagios Core

Install Nagios Core:

sudo apt update && sudo apt install -y nagios4 nagios-plugins nagios-nrpe-plugin
sudo systemctl enable nagios4

Access the Nagios web interface at http://pi-ip/nagios4. Default credentials are nagiosadmin with the password you set during installation.

Add devices to monitor:

Create host definitions in /etc/nagios4/conf.d/. For example, to monitor your router:

# /etc/nagios4/conf.d/network-devices.cfg
define host {
    use             generic-host
    host_name       router
    alias           Home Router
    address         192.168.1.1
    max_check_attempts  3
    check_period    24x7
    notification_interval  30
    notification_period    24x7
}

define host {
    use             generic-host
    host_name       nas
    alias           File Server
    address         192.168.1.100
}

define service {
    use                 generic-service
    host_name           router
    service_description PING
    check_command       check_ping!100.0,20%!500.0,60%
}

Add similar definitions for every device you want to monitor — NAS, access points, smart home hubs, printers, and desktop machines. Nagios pings each device at configurable intervals and alerts you when a device stops responding.

InfluxDB and Grafana Dashboard

Install InfluxDB:

sudo apt install -y influxdb influxdb-client
sudo systemctl enable influxdb

Install Grafana:

sudo apt install -y grafana
sudo systemctl enable grafana-server
sudo systemctl start grafana-server

Access Grafana at http://pi-ip:3000 (default login: admin/admin).

Create a speed test data collector:

sudo apt install -y speedtest-cli

Create a script that runs speedtest every 30 minutes and writes results to InfluxDB:

#!/bin/bash
# /home/pi/speedtest-logger.sh
RESULT=$(speedtest-cli --simple)
DOWNLOAD=$(echo "$RESULT" | grep "Download" | awk '{print $2}')
UPLOAD=$(echo "$RESULT" | grep "Upload" | awk '{print $2}')
PING=$(echo "$RESULT" | grep "Ping" | awk '{print $2}')

curl -i -XPOST 'http://localhost:8086/write?db=network' 
  --data-binary "speedtest download=${DOWNLOAD},upload=${UPLOAD},ping=${PING}"

Add to crontab: */30 * * * * /home/pi/speedtest-logger.sh

In Grafana, add InfluxDB as a data source and create panels showing download speed, upload speed, and latency over time. Within a day, you will have clear evidence of your ISP’s actual performance versus advertised speeds.

Additional data collectors:

Telegraf: Collects system metrics (CPU, RAM, disk, network traffic) from the Pi itself and other Linux machines
SNMP: Queries managed switches and routers for port-level traffic statistics
Ping collector: Logs round-trip times to key hosts (Google DNS, your office, gaming servers) every minute

🛒 Recommended: Waveshare PCIe to M.2 Adapter (D) for Raspberry Pi 5 — NVMe storage handles constant database writes from monitoring without wearing out SD cards.

Configuring Alerts and Notifications

Nagios email alerts: Configure Nagios to send email notifications when a device goes down or a service becomes unreachable. Edit /etc/nagios4/objects/contacts.cfg with your email address.

Telegram alerts: For instant notifications on your phone, integrate Nagios with Telegram via a notification script. Create a Telegram bot and add a custom notification command that sends alerts to your Telegram chat.

Grafana alerts: Grafana can trigger alerts based on metric thresholds. Set up alerts for: ISP speed dropping below a threshold, devices going offline, disk usage exceeding limits, or temperature exceeding safe levels.

What to Monitor on an Indian Network

ISP performance:

Download/upload speed vs plan speed (run speed tests every 30 minutes)
Latency to Indian servers (Mumbai, Chennai, Delhi data centres)
DNS resolution time (is your ISP’s DNS slow?)
Packet loss percentage (common during peak hours on some Indian ISPs)

Home network:

Wi-Fi access point uptime and signal quality
Smart home devices (bulbs, cameras, sensors) — these often silently disconnect
NAS and file server availability
Printer online status

Office network:

Internet gateway availability and failover status
VPN tunnel status
Critical application servers (ERP, email, CRM)
UPS battery status and power input

Frequently Asked Questions

Can a Raspberry Pi handle monitoring 50+ devices?

Yes. Nagios on a Pi 5 4GB comfortably monitors 50-100 devices with standard ping and port checks. The bottleneck is usually database writes if you collect metrics at very high frequency. Use NVMe storage for write-heavy monitoring.

Is there a simpler alternative to Nagios?

Yes. Uptime Kuma is a modern, lightweight monitoring tool with a clean web interface. Install it with Docker: docker run -d -p 3001:3001 louislam/uptime-kuma. It monitors URLs, ports, and ping with built-in notifications — easier to set up than Nagios, though less powerful for complex monitoring.

How much storage does monitoring data use?

InfluxDB is efficient with time-series data. Monitoring 20 devices with 5-minute intervals generates roughly 100MB per month. A year of data fits easily on a 32GB SD card. For high-frequency monitoring (every 30 seconds across 50+ devices), use NVMe storage.

Can I access the monitoring dashboard from my phone?

Yes. Grafana’s web interface is responsive and works on mobile browsers. For remote access outside your home network, use Tailscale VPN (free) to securely access the Pi’s Grafana from anywhere.

Does this work with JioFiber/Airtel/ACT?

Yes. The monitoring system is independent of your ISP — it just measures what the ISP delivers. In fact, one of the most valuable uses is documenting ISP performance over time to support complaints or plan upgrades.

Conclusion

A Raspberry Pi network monitor transforms your understanding of your network. Instead of guessing why the internet feels slow or not knowing when devices go offline, you have concrete data and immediate alerts. The Nagios + InfluxDB + Grafana stack provides enterprise-grade monitoring at the cost of a single Pi and an afternoon of setup.

Start by monitoring your ISP speed and pinging your critical devices. Once you see the first dashboard come to life with real data, you will want to monitor everything.

Get your Raspberry Pi 5 for network monitoring from Zbotic — fast shipping across India.