LibreNMS Snmpsim helpers

Be sure to install snmpsim first by: Making sure pip is installed For CentOS 7 sudo yum install epel-release sudo yum -y install python-pip sudo pip install snmpsim

snmpwalk and snmprec files for simulating devices

• Using snmpsim
  • Starting snmpsim
  • systemd automation
  • Add a new host to LibreNMS
  • Changing the simulated device
• Creating Captures
  • Snmprec
  • Snmpwalk

Using snmpsim

Add localhost aliases

Edit your /etc/hosts file

127.0.0.1 localhost snmpsim

You may add more if you would like to add multiple test devices to LibreNMS.

Starting snmpsim

Use the provided script

./snmpsim.sh

Or run by hand

snmpsimd.py --data-dir=./captures --agent-udpv4-endpoint=127.0.0.1:1161

systemd automation

Using systemd, we can automatically start snmpsimd.py whenever a connection is started to udp:1161 and restart it whenever a capture file is changed, added, or removed.

• Copy the systemd files to /etc/systemd/system

cp scripts/systemd/* /etc/systemd/system/

• Edit snmpsimd.service and snmpsim-watch.path and put in the correct paths and user.

• Enable and start the proper units:

systemctl enable --now snmpsimd.socket snmpsim-watch.path

Add a new host to LibreNMS

Use either the command line or the webui to add a new host to LibreNMS.

Hostname: snmpsim (or anything you added to hosts) Community:

./addhost.php snmpsim ucd v2c 1161

Changing the simulated device

You may either remove then re-add the device or simply change the SNMP community string. Re-run discovery and poller.

Alternatively, you could add multiple hostname alias' to the /etc/hosts file.

Creating capture files

Two formats are allowed snmprec and snmpwalk. Try to review files for private information before submitting to this repository.

Snmprec

Basic usage

snmprec.py --agent-udpv4-endpoint=HOSTNAME --community=COMMUNITY

See the snmpsim documentation for details on capturing snmprec files.

Snmpwalk

Snmpwalk files must be in number only format (-On), otherwise, snmpsim will not start.
translate-snmpwalk.py is provide to convert user provide snmpwalks to a number only format.