Introduction

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I run an APC Smart‑UPS 1500 with an AP9630 Network Management Card (NMC) in my homelab. A Raspberry Pi handles Network UPS Tools (NUT), which lets me gracefully shut down power‑sensitive systems like my NAS.

USB monitoring with NUT worked fine, but SNMP was a different story. The NMC was exposing newer OIDs that the packaged version of NUT simply didn’t understand. The fix was to build a newer version of NUT from source - and that’s what this guide walks through.

Why SNMP?

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USB monitoring works well enough for basic shutdown automation. But once I started integrating Home Assistant dashboards and automations, the USB HID driver felt extremely limited. SNMP exposes far richer telemetry: load, battery capacity, runtime estimates, temperature, alarms, and more.

The problem: outdated NUT packages

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A simple:

sudo apt-get update && sudo apt-get upgrade

…won’t help. Debian‑based distros typically ship NUT 2.7.x, while upstream is already at 2.8+. The SNMP driver improvements you need are only in the newer releases.

You can grab the latest tarball from:
https://networkupstools.org/download.html

Configuring SNMPv3 on the APC AP9630

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On the AP9630 NMC, enable and configure SNMPv3:

Configuration → Network → SNMPv3 → Access
Enable SNMPv3.

Configuration → Network → SNMPv3 → User Profiles
Create a user with:

• Security Level: authPriv
• Authentication Protocol: SHA
• Privacy Protocol: AES
• Authentication Passphrase: your choice
• Privacy Passphrase: your choice

snmpwalk -v3 -u "nutuser" -l authPriv \
  -a SHA -A "<Auth Passphrase>" \
  -x AES -X "<Priv Passphrase>" \
  <NMC IP> 1.3.6.1.2.1.3

Installing a newer version of NUT

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1. Back up your existing configuration

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sudo cp -a /etc/nut ~/nut-backup-$(date +%Y%m%d-%H%M)/

2. Remove the distro‑packaged NUT

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sudo apt remove nut nut-server nut-client

A reboot here avoids leftover processes interfering.

3. Download and extract the latest NUT release

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wget https://www.networkupstools.org/source/2.8/nut-2.8.4.tar.gz
tar xzf nut-2.8.4.tar.gz
cd nut-2.8.4

4. Configure the build

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Install packages required to build

sudo apt install build-essential libusb-1.0-0-dev libsnmp-dev libssl-dev libtool automake autoconf pkg-config libgd-dev

Replace nut with the user/group you want NUT to run under.

./configure \
  --with-usb \
  --with-snmp \
  --with-systemd \
  --with-serial \
  --with-openssl \
  --prefix=/usr \
  --sysconfdir=/etc/nut \
  --with-user=nut \
  --with-group=nut

5. Build and install

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make
sudo make install
sudo make install-as-root

6. Restore or recreate your configuration

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Copy your backed‑up files or create fresh ones (examples below).

7. Restart NUT

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sudo systemctl restart nut

8. Verify the driver is running

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systemctl status nut-driver@ups.service

(Substitute ups with your driver name.)

Fixing USB HID permission issues (if using USB + SNMP)

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If the USB driver fails to claim the device:

1. Check for udev rules

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ls -l /etc/udev/rules.d/ | grep nut

2. Identify your UPS

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lsusb

Example:

Bus 001 Device 003: ID 051d:0003 American Power Conversion UPS

3. Check permissions

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ls -l /dev/bus/usb/001/003

You should see group ownership matching your NUT user.

4. If needed, copy the default rules

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sudo cp /lib/udev/rules.d/62-nut-usbups.rules /etc/udev/rules.d/
sudo udevadm control --reload-rules
sudo udevadm trigger

ps aux | grep -E "snmp-ups|usbhid-ups"

If something still isn’t working, inspect logs:

sudo journalctl -u nut-driver@apc_snmp.service -n 50
sudo journalctl -u nut-driver@ups.service -n 50

My NUT Configuration

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I run both USB and SNMP drivers.

/etc/nut/nut.conf

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MODE=netserver

/etc/nut/ups.conf

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maxretry = 3

[apc_snmp]
  driver = snmp-ups
  port = <NMC HOSTNAME/IP>
  desc = "APC Smart-UPS via SNMPv3"
  snmp_version = v3
  secLevel = authPriv
  secName = nutuser
  authProtocol = SHA
  authPassword = <Authentication Passphrase>
  privProtocol = AES
  privPassword = <Privacy Passphrase>

[ups]
  driver = usbhid-ups
  desc = "APC 1500"
  port = auto
  vendorid = 051D
  productid = 0003

upsc apc_snmp@localhost

/etc/nut/upsd.users

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[upsmon]
  password = <PASSWORD>
  upsmon primary
  actions = SET
  instcmds = ALL

[observer]
  password = <PASSWORD>
  upsmon secondary

Final checks

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Reboot your NUT host and confirm:

• SNMP driver starts cleanly
• USB driver (if used) claims the device
• upsc <name>@localhost returns data
• Home Assistant or other consumers can poll NUT

Once everything is stable, you’ll have a far richer UPS monitoring setup than USB alone can offer.