Network Monitoring Tools Every Admin Should Know
You can't fix what you can't see. These network monitoring tools help admins identify problems before users start complaining.
Network problems have a way of becoming everyone's problem. When the Wi-Fi is slow, the VPN drops, or a critical application can't reach its server, users notice immediately. Network monitoring tools give administrators visibility into what's happening across their infrastructure, enabling proactive troubleshooting instead of reactive firefighting.
Free and Open Source Tools
PRTG Network Monitor (Free Tier)
PRTG offers up to 100 sensors for free, which is enough for small networks. Each sensor monitors one aspect of a device — a port's bandwidth, a server's CPU usage, a switch's uptime. The web interface is intuitive, and alerts can be sent via email, SMS, or push notification. For small US businesses without a monitoring budget, PRTG's free tier is hard to beat.
Zabbix
Fully open source with no artificial limitations, Zabbix scales from small offices to enterprise data centers. It monitors via SNMP, IPMI, JMX, and custom scripts. The learning curve is steeper than PRTG, but the flexibility is unmatched. If you have the Linux administration skills to deploy it, Zabbix is one of the most powerful monitoring platforms available at any price.
LibreNMS
An auto-discovering network monitoring system built on SNMP. LibreNMS excels at network device monitoring — switches, routers, firewalls, and access points. It automatically discovers devices on your network, starts collecting data, and alerts you to problems. The community is active, and documentation is solid.
Cloud-Based Solutions
For organizations that prefer managed solutions, cloud-based monitoring eliminates the need to maintain your own monitoring server. Datadog, LogicMonitor, and Auvik offer SaaS platforms that monitor on-premises and cloud infrastructure from a single dashboard. Auvik, in particular, has gained popularity among US managed service providers (MSPs) for its automated network mapping and configuration backup features.
What to Monitor
Don't try to monitor everything — you'll drown in data. Start with these essentials:
- Uptime/availability — Is each critical device online? Simple but fundamental
- Bandwidth utilization — Which links are approaching capacity? Where are the bottlenecks?
- Error rates — CRC errors, packet drops, and interface errors indicate physical layer problems
- Latency — Round-trip time to critical services and between sites
- CPU and memory — On managed switches, firewalls, and routers, high resource usage signals problems
The goal of network monitoring isn't to collect data — it's to turn data into actionable alerts. A dashboard nobody looks at and alerts nobody reads provide zero value. Configure meaningful thresholds and route alerts to people who can act on them.