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 and shows how they move across the network. And it doesn’t try to be a monitoring system — it’s an inventory and topology tracker, plain and simple.
For any environment where it matters what port a device is plugged into — NetDisco delivers that answer.
What It Knows and Shows
| Capability | Practical Benefit |
| Topology autodiscovery | Uses SNMP/ARP/CDP/LLDP to trace actual network links |
| MAC/IP resolution | Lets you search devices by IP, MAC, port, switch, or hostname |
| History tracking | Keeps logs of host movement and port state over time |
| Web-based GUI | Fast navigation between switches, ports, and connected endpoints |
| PostgreSQL backend | Reliable data store that scales for larger infrastructures |
How It Compares to the Usual Suspects
| Tool | Primary Role | What NetDisco Does Differently |
| LibreNMS | Monitors status and metrics | NetDisco tracks connections, not performance |
| Zabbix | Full-stack monitoring with thresholds | NetDisco focuses purely on topology and inventory |
| PRTG | Sensors and alerts | NetDisco maps what’s on the wire and who’s using it |
| NetBox | Inventory and IPAM | NetDisco discovers, NetBox documents |
| Switch CLI | Manual checks | NetDisco automates what admins used to grep by hand |
Installation Notes
NetDisco runs on Linux with a PostgreSQL backend. It uses Perl and a number of daemonized background processes.
Typical setup:
1. Install PostgreSQL and Perl dependencies
2. Clone or install NetDisco from packages
3. Configure SNMP community strings for device polling
4. Launch the backend services and web frontend
5. Start discovery and watch the map build itself
Best deployed on a central server with access to core switches.
Where It Belongs
University or campus networks with lots of lateral traffic
MSPs who need a living map of client infrastructure
Enterprises with hundreds of VLANs and unmanaged edge ports
Teams that need traceability more than alerts
Scenarios where rogue devices need to be found, fast
NetDisco isn’t chasing trends. It’s built for admins who ask: “Where is this MAC address coming from, and when did it move?” If that question matters in your environment, you’ll understand its value immediately.