Jt-snmpd: a read-only SNMP agent for Windows hosts

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Windows’ built-in SNMP Service is deprecated, and even before that it never gave
LibreNMS much to work with. No disk I/O, no drive temperatures, not much of an
inventory. I wanted those, so I wrote a replacement for the Windows side.

jt-snmpd, GPL-3.0.
Project site: jt-snmpd — a complete replacement for the Windows SNMP Service
Source: GitHub - jasoncheng7115/jt-snmpd: Read-only SNMP agent for Windows. Replaces the deprecated Microsoft SNMP Service and feeds LibreNMS over standard MIBs — disk SMART, sensors, inventory. No kernel driver, MSI/GPO ready. · GitHub

It’s an agent, not a plugin. Nothing changes on the LibreNMS server. No patch,
no agent script, no smartctl. It speaks standard MIBs and gets discovered as an
ordinary Windows device.

I ran both agents on the same machine, one after the other, polled by the same
LibreNMS, so the comparison is fair. What it added:

  • Inventory: chassis, mainboard, CPU, DIMMs and disks, parsed out of SMBIOS
  • Disk SMART over NET-SNMP-EXTEND-MIB, the route LibreNMS already reads
  • Sensors: drive temperature and ACPI thermal zone, carrying the thresholds the
    firmware declares
  • Disk I/O, and 4 memory pools instead of 2 (Cached and Swap on top)

One thing it reports less of, on purpose. The built-in service publishes every
NDIS filter driver as its own interface, which is 9 ports on my laptop and only
2 of them real. jt-snmpd publishes the 2, and pins ifIndex to the NET_LUID so a
driver update doesn’t orphan your RRDs.

Screenshots of all of it side by side:

Things worth knowing before you try it:

  • Read-only. GET, GETNEXT and GETBULK, no SET, no traps.
  • v2c only. v3 isn’t done yet.
  • It makes no outbound connections at all.
  • The MSI isn’t code signed, so SmartScreen will complain. Every release ships
    a SHA-256.
  • Upgrading by double-click brings up Windows Installer’s “Files in use” page.
    A silent install doesn’t.

Tested on real hardware: Windows 10 and 11, Server 2016 and 2022, including a
domain controller. If anyone runs it on a bigger estate than mine, I’d like to
hear how it goes.

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