NetDisco: Honest, Open Network Mapping That Knows What’s Plugged Where Some tools show you graphs. Others show logs. NetDisco shows connections — the real, physical and logical links between devices on a network. It quietly crawls your switches and routers via SNMP and ARP, then builds a picture of what’s connected where. No guesswork, no manual diagrams.

It’s been around for years and is still actively maintained. Not because it’s flashy, but because it does one job well: it tracks endpoints a

OpenNMS: Enterprise-Grade Network Monitoring That You Actually Control If there’s a list of open-source tools that quietly power serious infrastructure, OpenNMS is somewhere near the top. It doesn’t get hyped much — partly because it’s complex, partly because it’s already been doing its job behind the scenes for years.

It’s not a “get started in 5 minutes” solution. But for teams that want to monitor everything — from physical switches to SNMP traps, custom apps, and even remote sites — and kee

LanTopoLog: Simple Network Mapping Without the Bloat LanTopoLog is a lightweight tool built for a very specific purpose — discovering network topology using SNMP and drawing maps based on real switch port data. It’s not a monitoring suite. It won’t flood you with metrics or graphs. Instead, it gives a clean and functional view of how your network is physically wired.

Ideal for small to mid-sized networks where visibility is limited and documentation is outdated, LanTopoLog offers a quick way to

PRTG Network Monitor: All-in-One Monitoring That Actually Scales Most tools force a trade-off: flexibility or simplicity. PRTG does a solid job of walking that line. It offers agentless monitoring out of the box, SNMP support, NetFlow, WMI, packet sniffing, web probes — and somehow still manages to feel understandable to new admins without losing power for the seasoned ones.

Developed by Paessler, PRTG runs on Windows and gives a single-pane view of your network, devices, apps, and traffic — fr