Configure custom SNMP MIBs for vendor-specific monitoring with SNMP v2c and v3

Install SNMP daemon and utilities

Install the SNMP daemon, client utilities, and MIB browser tools needed for vendor-specific monitoring.

sudo apt update
sudo apt install -y snmp snmpd snmp-mibs-downloader libsnmp-dev
sudo download-mibs

sudo dnf install -y net-snmp net-snmp-utils net-snmp-devel
sudo dnf install -y epel-release
sudo dnf install -y net-snmp-perl

Configure MIB search paths

Set up the directory structure and configure where SNMP tools look for MIB files.

sudo mkdir -p /usr/share/snmp/mibs/vendor
sudo mkdir -p /etc/snmp/mibs

# Configure MIB search paths
mibs +ALL
mibdirs /usr/share/snmp/mibs:/usr/share/snmp/mibs/vendor:/etc/snmp/mibs

Disable MIB warnings for unknown objects
dontLogTCPWrappersConnects yes
logTimestamp yes

Download and install vendor MIB files

Download MIB files from your vendor's support site and install them properly. This example shows Cisco and Dell MIBs.

# Create vendor-specific directories
sudo mkdir -p /usr/share/snmp/mibs/vendor/cisco
sudo mkdir -p /usr/share/snmp/mibs/vendor/dell
sudo mkdir -p /usr/share/snmp/mibs/vendor/hp

# Download example Cisco MIBs (replace URLs with actual vendor links)
cd /tmp
wget https://www.cisco.com/c/dam/en/us/td/docs/ios-xml/ios/snmp/mibs/all-mibs.zip
unzip all-mibs.zip
sudo cp *.my /usr/share/snmp/mibs/vendor/cisco/

Set proper permissions
sudo chown root:root /usr/share/snmp/mibs/vendor/cisco/*
sudo chmod 644 /usr/share/snmp/mibs/vendor/cisco/*

Configure SNMP v2c community strings

Set up community-based authentication for SNMP v2c monitoring with read-only and read-write access.

# SNMP v2c community configuration
Read-only community for monitoring
rocommunity monitoring_readonly default
rocommunity6 monitoring_readonly default

Read-write community for configuration (use sparingly)
rwcommunity config_readwrite localhost

System information
sysLocation "Data Center A, Rack 23"
sysContact "network-admin@example.com"
sysName "network-switch-01"

Agent address and port
agentAddress udp:161,udp6:[::1]:161

Disable default public community
rocommunity public default

Disk and load monitoring
disk / 10000
load 12 14 14

Process monitoring
proc sshd
proc snmpd

Configure SNMP v3 users and authentication

Create SNMP v3 users with authentication and privacy encryption for secure monitoring.

# Stop snmpd to modify v3 configuration
sudo systemctl stop snmpd

# Add SNMP v3 configuration to existing file

SNMP v3 User configuration
Auth protocol: MD5 or SHA
Privacy protocol: DES or AES

Read-only user with authentication only
createUser monitor_user MD5 "StrongAuthPassword123!"
rouser monitor_user

Read-write user with authentication and privacy
createUser admin_user SHA "StrongAuthPassword456!" AES "StrongPrivPassword789!"
rwuser admin_user

Read-only user with both auth and privacy
createUser secure_monitor SHA "MonitorAuthPass321!" AES "MonitorPrivPass654!"
rouser secure_monitor

Security model configuration
com2sec notConfigUser default public
com2sec configUser localhost config_readwrite
com2sec readUser default monitoring_readonly

group notConfigGroup v1 notConfigUser
group notConfigGroup v2c notConfigUser
group configGroup v2c configUser
group readGroup v2c readUser

view systemonly included .1.3.6.1.2.1.1
view systemonly included .1.3.6.1.2.1.25.1

access notConfigGroup "" any noauth exact systemonly none none
access configGroup "" any noauth exact all all none
access readGroup "" any noauth exact all none none

Configure vendor-specific OID monitoring templates

Create monitoring templates for common vendor-specific metrics using their custom MIBs.

# Cisco device monitoring OIDs
CPU utilization (5-minute average)
ciscoMemoryPoolUsed .1.3.6.1.4.1.9.9.48.1.1.1.5
ciscoCPUTotal5min .1.3.6.1.4.1.9.9.109.1.1.1.1.8

Interface specific metrics
ciscoInterfaceAlias .1.3.6.1.4.1.9.9.46.1.3.1.1.18
ciscoInterfaceDescription .1.3.6.1.4.1.9.9.46.1.6.1.1.14

Dell PowerEdge server monitoring
Temperature sensors
dellTemperatureProbeReading .1.3.6.1.4.1.674.10892.1.700.20.1.6
dellTemperatureProbeStatus .1.3.6.1.4.1.674.10892.1.700.20.1.5

Power supply status
dellPowerSupplyStatus .1.3.6.1.4.1.674.10892.1.600.12.1.5
dellPowerSupplyType .1.3.6.1.4.1.674.10892.1.600.12.1.7

Fan status
dellFanStatus .1.3.6.1.4.1.674.10892.1.700.12.1.5
dellFanSpeed .1.3.6.1.4.1.674.10892.1.700.12.1.6

RAID controller status
dellVirtualDiskStatus .1.3.6.1.4.1.674.10892.1.1100.20.1.4
dellPhysicalDiskStatus .1.3.6.1.4.1.674.10892.1.1100.25.1.4

Create monitoring scripts for custom metrics

Develop scripts to query vendor-specific OIDs and format the output for monitoring systems.

#!/bin/bash

SNMP vendor monitoring script
Usage: ./snmp-vendor-monitor.sh   

TARGET_IP="$1"
COMMUNITY="$2"
VERSION="$3"

if [ $# -ne 3 ]; then
    echo "Usage: $0   "
    echo "Version: 2c or 3"
    exit 1
fi

check_cisco_metrics() {
    echo "=== Cisco Device Metrics ==="
    
    # CPU utilization
    CPU=$(snmpget -v${VERSION} -c${COMMUNITY} ${TARGET_IP} .1.3.6.1.4.1.9.9.109.1.1.1.1.8.1 2>/dev/null | cut -d' ' -f4)
    echo "CPU 5min avg: ${CPU}%"
    
    # Memory utilization
    MEM_USED=$(snmpget -v${VERSION} -c${COMMUNITY} ${TARGET_IP} .1.3.6.1.4.1.9.9.48.1.1.1.5.1 2>/dev/null | cut -d' ' -f4)
    MEM_TOTAL=$(snmpget -v${VERSION} -c${COMMUNITY} ${TARGET_IP} .1.3.6.1.4.1.9.9.48.1.1.1.6.1 2>/dev/null | cut -d' ' -f4)
    if [ -n "$MEM_USED" ] && [ -n "$MEM_TOTAL" ]; then
        MEM_PERCENT=$((MEM_USED * 100 / MEM_TOTAL))
        echo "Memory usage: ${MEM_PERCENT}% (${MEM_USED}/${MEM_TOTAL})"
    fi
}

check_dell_metrics() {
    echo "=== Dell PowerEdge Metrics ==="
    
    # Temperature sensors
    snmpwalk -v${VERSION} -c${COMMUNITY} ${TARGET_IP} .1.3.6.1.4.1.674.10892.1.700.20.1.6 2>/dev/null | while read line; do
        TEMP=$(echo $line | cut -d' ' -f4)
        SENSOR=$(echo $line | cut -d'.' -f2)
        echo "Temperature sensor ${SENSOR}: ${TEMP}°C"
    done
    
    # Power supply status
    snmpwalk -v${VERSION} -c${COMMUNITY} ${TARGET_IP} .1.3.6.1.4.1.674.10892.1.600.12.1.5 2>/dev/null | while read line; do
        STATUS=$(echo $line | cut -d' ' -f4)
        PSU=$(echo $line | cut -d'.' -f2)
        case $STATUS in
            1) STATUS_TEXT="Other" ;;
            2) STATUS_TEXT="Unknown" ;;
            3) STATUS_TEXT="OK" ;;
            4) STATUS_TEXT="Non-critical" ;;
            5) STATUS_TEXT="Critical" ;;
            6) STATUS_TEXT="Non-recoverable" ;;
            *) STATUS_TEXT="Unknown($STATUS)" ;;
        esac
        echo "Power Supply ${PSU}: ${STATUS_TEXT}"
    done
}

Determine device type and check appropriate metrics
SYS_OID=$(snmpget -v${VERSION} -c${COMMUNITY} ${TARGET_IP} .1.3.6.1.2.1.1.2.0 2>/dev/null | cut -d' ' -f4)

case $SYS_OID in
    .1.3.6.1.4.1.9.) check_cisco_metrics ;;
    .1.3.6.1.4.1.674.) check_dell_metrics ;;
    *) echo "Unknown or unsupported device type: $SYS_OID" ;;
esac

sudo chmod +x /usr/local/bin/snmp-vendor-monitor.sh

Configure SNMP v3 authentication script

Create a script for SNMP v3 monitoring with authentication and privacy.

#!/bin/bash

SNMP v3 monitoring script with authentication and privacy
Usage: ./snmp-v3-monitor.sh    

TARGET_IP="$1"
USERNAME="$2"
AUTH_PASS="$3"
PRIV_PASS="$4"

if [ $# -ne 4 ]; then
    echo "Usage: $0    "
    exit 1
fi

SNMP v3 with SHA authentication and AES privacy
SNMP_OPTS="-v3 -l authPriv -u ${USERNAME} -a SHA -A ${AUTH_PASS} -x AES -X ${PRIV_PASS}"

echo "=== SNMP v3 Device Monitor ==="
echo "Target: $TARGET_IP"
echo "User: $USERNAME"
echo ""

System information
echo "System Information:"
SYS_NAME=$(snmpget $SNMP_OPTS ${TARGET_IP} .1.3.6.1.2.1.1.5.0 2>/dev/null | cut -d'"' -f2)
SYS_DESCR=$(snmpget $SNMP_OPTS ${TARGET_IP} .1.3.6.1.2.1.1.1.0 2>/dev/null | cut -d'"' -f2)
UPTIME=$(snmpget $SNMP_OPTS ${TARGET_IP} .1.3.6.1.2.1.1.3.0 2>/dev/null | cut -d')' -f1 | cut -d'(' -f2)

echo "  Name: $SYS_NAME"
echo "  Description: $SYS_DESCR"
echo "  Uptime: $UPTIME"
echo ""

Interface statistics
echo "Interface Statistics:"
snmpwalk $SNMP_OPTS ${TARGET_IP} .1.3.6.1.2.1.2.2.1.2 2>/dev/null | head -5 | while read line; do
    INTERFACE=$(echo $line | cut -d'"' -f2)
    INDEX=$(echo $line | cut -d'.' -f2 | cut -d' ' -f1)
    
    # Get interface statistics
    IN_BYTES=$(snmpget $SNMP_OPTS ${TARGET_IP} .1.3.6.1.2.1.2.2.1.10.${INDEX} 2>/dev/null | awk '{print $NF}')
    OUT_BYTES=$(snmpget $SNMP_OPTS ${TARGET_IP} .1.3.6.1.2.1.2.2.1.16.${INDEX} 2>/dev/null | awk '{print $NF}')
    
    echo "  ${INTERFACE}: IN=${IN_BYTES} bytes, OUT=${OUT_BYTES} bytes"
done

sudo chmod +x /usr/local/bin/snmp-v3-monitor.sh

Start and enable SNMP daemon

Enable the SNMP daemon to start automatically and begin accepting monitoring requests.

sudo systemctl enable --now snmpd
sudo systemctl status snmpd

Configure firewall rules

Open the SNMP port for monitoring while restricting access to trusted networks only.

# Allow SNMP from monitoring network only
sudo ufw allow from 192.168.1.0/24 to any port 161
sudo ufw allow from 203.0.113.0/24 to any port 161
sudo ufw reload

# Allow SNMP from monitoring network only
sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="192.168.1.0/24" port protocol="udp" port="161" accept'
sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="203.0.113.0/24" port protocol="udp" port="161" accept'
sudo firewall-cmd --reload

Prometheus SNMP Exporter configuration

Configure the SNMP exporter to use your custom MIBs and vendor-specific OIDs. You can reference our Prometheus monitoring setup guide for the complete monitoring stack.

# SNMP Exporter configuration for vendor devices
global:
  scrape_timeout: 10s

modules:
  cisco_device:
    walk:
      - 1.3.6.1.2.1.1  # System information
      - 1.3.6.1.4.1.9.9.109.1.1.1.1.8  # CPU utilization
      - 1.3.6.1.4.1.9.9.48.1.1.1  # Memory pools
      - 1.3.6.1.2.1.2.2.1  # Interface statistics
    version: 3
    auth:
      username: secure_monitor
      password: MonitorAuthPass321!
      auth_protocol: SHA
      priv_protocol: AES
      priv_password: MonitorPrivPass654!
      security_level: authPriv
  
  dell_server:
    walk:
      - 1.3.6.1.2.1.1  # System information
      - 1.3.6.1.4.1.674.10892.1.700.20.1  # Temperature sensors
      - 1.3.6.1.4.1.674.10892.1.600.12.1  # Power supplies
      - 1.3.6.1.4.1.674.10892.1.700.12.1  # Fans
      - 1.3.6.1.4.1.674.10892.1.1100.20.1  # Virtual disks
    version: 2c
    community: monitoring_readonly

Create monitoring alerts

Set up alerting rules for vendor-specific metrics. This integrates well with Prometheus AlertManager for comprehensive notification handling.

groups:
  - name: cisco_alerts
    rules:
      - alert: CiscoCPUHigh
        expr: snmp_cisco_cpu_5min > 80
        for: 5m
        labels:
          severity: warning
          device_type: cisco
        annotations:
          summary: "Cisco device CPU utilization high"
          description: "CPU utilization is {{ $value }}% on device {{ $labels.instance }}"
      
      - alert: CiscoMemoryHigh
        expr: (snmp_cisco_memory_used / snmp_cisco_memory_total) * 100 > 85
        for: 5m
        labels:
          severity: critical
          device_type: cisco
        annotations:
          summary: "Cisco device memory utilization critical"
          description: "Memory utilization is {{ $value }}% on device {{ $labels.instance }}"
  
  - name: dell_alerts
    rules:
      - alert: DellTemperatureHigh
        expr: snmp_dell_temperature > 70
        for: 3m
        labels:
          severity: warning
          device_type: dell
        annotations:
          summary: "Dell server temperature high"
          description: "Temperature sensor reading {{ $value }}°C on server {{ $labels.instance }}"
      
      - alert: DellPowerSupplyFailure
        expr: snmp_dell_power_supply_status != 3
        for: 0m
        labels:
          severity: critical
          device_type: dell
        annotations:
          summary: "Dell server power supply failure"
          description: "Power supply status is {{ $value }} (not OK) on server {{ $labels.instance }}"