Adding a new VM to existing LibreNMS home lab monitoring setup.

See LibreNMS initial setup for the full setup.

A complete walkthrough for deploying the SNMP client to a new VM and adding it to LibreNMS for monitoring. Starting point assumes setup-snmp.sh exists at ~/Scripts/ on lpt-HP only.

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Prerequisites

• setup-snmp.sh present at ~/Scripts/ on lpt-HP (192.168.1.100)
• SSH access from lpt-HP to the target VM
• ~/Scripts/ directory already exists on the target VM
• LibreNMS running on librenms-vm (192.168.1.176)
• Target VM has a known static IP address

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Step 1 — Copy the Script to the Target VM

From lpt-HP, copy the script to the target VM. Replace <IP> with the target VM’s IP address.

scp ~/Scripts/setup-snmp.sh mark@<IP>:~/Scripts/

No output means success. The filename echoed back confirms the copy completed.

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Step 2 — SSH into the Target VM

ssh mark@<IP>

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Step 3 — Make the Script Executable and Run It

chmod +x ~/Scripts/setup-snmp.sh && ~/Scripts/setup-snmp.sh

The script installs snmpd, writes the configuration file, restarts and enables the service on boot, and opens UFW port 161 if UFW is active. The final line may show snmpwalk: command not found — this is expected and harmless. The SNMP service is running correctly regardless.

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Step 4 — Exit Back to lpt-HP

exit

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Step 5 — Verify SNMP Reachability from LibreNMS

SSH into librenms-vm:

ssh mark@192.168.1.176

Run a test poll against the new VM:

docker exec -it librenms snmpwalk -v2c -c public <IP> system

A successful response returns a block of SNMPv2-MIB::sys* entries. If you get a timeout instead, verify snmpd is running on the target VM and that UFW is not blocking UDP port 161 before continuing.

Exit librenms-vm:

exit

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Step 6 — Add the Device in LibreNMS

Open the LibreNMS web UI at 192.168.1.176:8000 and navigate to Devices → Add Device.

Enter the following values:

• Hostname/IP: <IP>
• SNMP version: v2c
• Community: public

Click Add Device. LibreNMS confirms with a message like:

Adding host <IP> community public port using udp
Device added [<IP>]

LibreNMS begins polling immediately. Memory, system info, and interface data should populate within seconds, confirming SNMP is fully operational.