This guide walks through collecting metrics from a network switch via SNMP, exposing them with the Prometheus SNMP Exporter, scraping from Prometheus (server at 192.168.56.200), and visualizing in Grafana.

• Switch SNMP agent: 172.20.2.83
• SNMP community (v2c): dfetest

1. Verify SNMP access to the switch

Confirm basic SNMP connectivity from the Prometheus host:

# On the Prometheus server
snmpwalk -v2c -c dfetest 172.20.2.83 sysUpTime.0

If the command returns a sysUpTime value, the agent is reachable and the community is corrrect.

2. Install the SNMP Exporter

Download and place the exporter under /usr/local. Adjust the architecture and version as needed.

# Example for Linux amd64
export VER=0.25.0
cd /usr/local
curl -LO https://github.com/prometheus/snmp_exporter/releases/download/v${VER}/snmp_exporter-${VER}.linux-amd64.tar.gz

# Extract and standardize the directory name
tar -xzf snmp_exporter-${VER}.linux-amd64.tar.gz
rm -f snmp_exporter-${VER}.linux-amd64.tar.gz
mv snmp_exporter-${VER}.linux-amd64 snmp_exporter

3. Generate an snmp.yml using the Config Generator

The SNMP Exporter relies on an snmp.yml generated from MIBs and module definitions. Build the generator and produce the configuration.

3.1 Install build prerequisites

yum -y install git gcc gcc-c++ make net-snmp net-snmp-utils net-snmp-libs net-snmp-devel

3.2 Build the generator and MIBs

# Ensure Go is installed and GOPATH is set (Go 1.18+)
# Build the generator
GO111MODULE=on go get github.com/prometheus/snmp_exporter/generator
cd ${GOPATH:-$HOME/go}/src/github.com/prometheus/snmp_exporter/generator

go build
make mibs

3.3 Configure generator.yml

Edit generator.yml to include a module for standard interface counters using the device’s community string. If your device only suports SNMPv1, set version: 1 accordingly.

# generator.yml (excerpt)
modules:
  if_mib:
    walk: [sysUpTime, interfaces, ifXTable]
    version: 2
    auth:
      community: dfetest
    lookups:
      - source_indexes: [ifIndex]
        lookup: ifAlias
      - source_indexes: [ifIndex]
        lookup: ifDescr
      - source_indexes: [ifIndex]
        lookup: 1.3.6.1.2.1.31.1.1.1.1   # ifName
    overrides:
      ifAlias: { ignore: true }
      ifDescr: { ignore: true }
      ifName:  { ignore: true }
      ifType:  { type: EnumAsInfo }

3.4 Generate snmp.yml

# From the generator directory
export MIBDIRS=mibs
./generator generate

# Deploy to the exporter directory
cp -f snmp.yml /usr/local/snmp_exporter/

4. Run and validate the SNMP Exporter

Start the exporter to serve metrics on port 9116.

cd /usr/local/snmp_exporter
./snmp_exporter --web.listen-address=":9116" --config.file="/usr/local/snmp_exporter/snmp.yml"

Open http://192.168.56.200:9116 in a browser, enter 172.20.2.83 into the Target field, submit, and confirm metrics are returned.

5. Set up a systemd service for the SNMP Exporter

Create a unit file to manage the exporter as a service.

cat >/etc/systemd/system/snmp_exporter.service <<'UNIT'
[Unit]
Description=Prometheus SNMP Exporter
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
ExecStart=/usr/local/snmp_exporter/snmp_exporter --web.listen-address=:9116 --config.file=/usr/local/snmp_exporter/snmp.yml
Restart=on-failure

[Install]
WantedBy=multi-user.target
UNIT

systemctl daemon-reload
systemctl enable snmp_exporter
systemctl start snmp_exporter

6. Configure Prometheus to scrape the switch via the exporter

Edit /usr/local/prometheus/prmoetheus.yml and add an SNMP scrape job. The relabel rules pass the device IP as the target parameter to the exporter and replace the scrape address with the exporter’s listener.

# /usr/local/prometheus/prometheus.yml (full example)

global:
  scrape_interval: 15s
  evaluation_interval: 15s

alerting:
  alertmanagers:
    - static_configs:
        - targets: []

rule_files: []

scrape_configs:
  - job_name: prometheus
    static_configs:
      - targets: ["localhost:9090"]

  - job_name: linux
    static_configs:
      - targets: ["192.168.56.201:9100"]
        labels:
          instance: linux

  - job_name: windows
    static_configs:
      - targets: ["192.168.56.1:9182"]
        labels:
          instance: windows

  - job_name: snmp-switch
    scrape_interval: 10s
    metrics_path: /snmp
    static_configs:
      - targets:
          - 172.20.2.83   # Switch IP
    # Uncomment to restrict to a specific generator module
    # params:
    #   module: [if_mib]
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: 192.168.56.200:9116   # SNMP exporter host:port

Reload Prometheus:

systemctl restart prometheus

Visit http://192.168.56.200:9090/targets and verify the snmp-switch job is up.

7. Import a Grafana dashboard

• Open Grafana and go to Dashboards → Import.
• Enter dashboard ID 10523 (SNMP monitoring dashboard from grafana.com).
• Click Change to generate a unique UID if prompted.
• Choose the Prometheus data source used above.
• Click Import and open the dashboard to view the SNMP metrics for 172.20.2.83.