The best network monitoring software tells you a switch, router or server is in trouble before your team does. Open source monitors give you a lot for free if someone can set them up, while cloud and commercial tools trade that work for a trial and a quicker start. Here are ten options in no particular order, with each free option explained.
Every network monitor promises alerts and dashboards. What decides whether it helps is the setup hours: how long it takes to add your devices, write sensible alert rules, and stop it waking you up for nothing. That's the bit worth judging, and it's rarely on the homepage.
Below are ten network and infrastructure monitors sorted alphabetically and in no particular order. I've taken every description from the maker's own website, re-checked today. Many in this category are open source or have a free community edition, so the free column has a lot of yeses, but free software still asks for your time.
Network monitors at a glance
Yes means an open source project, a free community edition or a free tier described on the maker's site, which can be limited by nodes or use. Trial only means a time-limited trial with no ongoing free version.
| Tool | Type | Good for | Free plan |
|---|---|---|---|
| Checkmk | Infrastructure monitoring | Small infrastructures wanting free monitoring | Yes |
| Domotz | Cloud network monitoring | MSPs and IT teams managing client sites | Trial only |
| Icinga | Open source monitoring | Teams wanting self-hosted, customisable checks | Yes |
| Nagios Core | Open source monitoring engine | Admins who want free, extensible monitoring | Yes |
| Netdata | Real-time metrics monitoring | Homelabs and very small setups | Yes |
| ntopng | Traffic analysis tool | Admins analysing live network traffic | Yes |
| Observium | Network monitoring platform | Home labs and SNMP-based networks | Yes |
| Pandora FMS | Flexible monitoring platform | Teams wanting one tool for many data types | Yes |
| SolarWinds Network Performance Monitor | Self-hosted network monitor | Larger IT teams monitoring many devices | Trial only |
| Zabbix | Open source observability | Teams monitoring networks, servers and cloud | Yes |
Ten monitoring tools for switches, routers and servers
Checkmk
Best for: Small infrastructures wanting network and server monitoring through a self-hosted Community edition that's free and open source, with commercial editions as you grow.
Domotz
Best for: MSPs and IT teams managing several client sites who want network monitoring and management, tested with unlimited devices in a 14-day trial.
Icinga
Best for: Teams wanting open source monitoring for networks, servers and wider IT infrastructure, with the freedom to customise checks and host it themselves.
Nagios Core
Best for: Admins wanting a free monitoring engine under the GPL v2 licence, with no licensing to manage and lots of room to extend it.
Netdata
Best for: Homelabs and very small setups wanting real-time infrastructure metrics on a Community tier that's free for 5 nodes for non-commercial use.
ntopng
Best for: Admins who need to see what's moving across the network, using a free open source Community edition, with commercial editions available.
Observium
Best for: Home labs and SNMP-based networks wanting monitoring and management on a Community edition that's free to everyone, with Professional and Enterprise editions.
Pandora FMS
Best for: Teams wanting one monitoring platform with open source roots for many kinds of data, starting from the free version on its downloads page.
SolarWinds Network Performance Monitor
Best for: Larger IT teams wanting self-hosted network performance monitoring, tried through a fully functional 30-day free trial before a quote.
Zabbix
Best for: Teams monitoring networks, servers and cloud from one open source platform with a free download, or through a separate cloud service with a trial.
CISA's warning about older SNMP versions
Most network monitors talk to your switches and routers over SNMP, so this matters more than it sounds. CISA, the US cybersecurity agency, says SNMPv3 should be the only version of SNMP you use, because with SNMPv1 or SNMPv2 an attacker could sniff network traffic and learn the community string. It recommends setting SNMPv3 to the highest security level a device offers, which on most devices is called authPriv.
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It's an older alert, but it's still CISA's guidance page on the subject, and it applies wherever you are. What it means for you: before you point any monitor at your network, check it supports SNMPv3 with authentication and encryption, and check your devices do too. If an old switch only speaks the older versions, put that on your replacement list.
Open source monitors and the hours they need
- Open source, self-hosted: free and flexible, but you'll install, update and back it up yourself.
- Free community editions: a good way in, though some limit nodes or exclude commercial use.
- Cloud monitors: quicker to start and handy for MSPs looking after several sites.
- Commercial self-hosted tools: polished and wide-ranging, usually arranged through a quote after a trial.
Rolling out monitoring on a small network
- List every device that would stop the business if it failed: internet line, firewall, core switch, servers, Wi-Fi.
- Confirm each one supports SNMPv3, and switch the older versions off where you can.
- Add those critical devices first, before you monitor anything else.
- Set alerts only for problems someone will act on, and send them to a person, not a shared inbox.
- Watch the alert noise for two weeks and tune the thresholds.
- Then widen coverage to printers, access points and the rest.
Monitoring sits alongside other network basics, so see my guides to locking down DHCP on your network and using a VPN to protect business traffic.
Do you make network monitoring software? Tool makers can ask to be considered for a featured place on this list.
My plain advice before you point a monitor at your network
If you've got someone technical who enjoys this kind of thing, an open source monitor will give you a huge amount for free, as long as you plan their hours honestly. If you're an MSP or a small team with no time to maintain another server, a cloud monitor with a trial is the quicker route.
Either way, start with SNMPv3 and your handful of critical devices. A monitor that watches five important things well beats one that watches everything and cries wolf.
Related: the solar page.
Frequently asked questions
What does network monitoring software do?
It checks your devices and connections around the clock and alerts you when something goes down, slows or behaves oddly.
Is there free network monitoring software?
Yes, plenty. Many tools are open source or have a free community edition. Some free tiers limit the number of nodes or exclude commercial use, so read the terms.
What is SNMP?
Simple Network Management Protocol, the standard way monitors read status from switches, routers and other kit. CISA advises using SNMPv3 only.
Do I need an agent on every device?
Not always. Network kit is usually read over SNMP, while servers and computers often need a small agent for detailed metrics.
Can an MSP monitor several client networks?
Yes. Some tools are built for multi-site monitoring, so check how each one separates clients and their alerts.
How do I stop too many alerts?
Alert only on things someone will act on, give each alert an owner, and review thresholds after the first couple of weeks.
