My snmpwalk output is incorrect. How can I fix it?

This article is being updated. Please be aware the content herein, not limited to version numbers and slight syntax changes, may not match the output from the most recent versions of Bright. This notation will be removed when the content has been updated.

If the switch cannot report the output of

snmpwalk -c public -v1 -On <switch> .1.3.6.1.2.1.17.7.1.2.2.1.2

Correctly then the showport command (and port detection in general) will not work out of the box. For example on a Dell S4148f-ON switch, SNMP failed to detect ports properly due to the switch not reporting snmpwalk output correctly.

A workaround for this issue is to create a custom control script in which you write your own logic to extract the MAC addresses from the switch and then MAP them to the correct port:

#!/bin/bash
# Example custom switch control script v1.0"

usage() {
  echo "$0 <command> <args>"
  echo " -h show this help"
  echo " --provides list available commands"
}

if [ -z "$1" -o "$1" == "-h" ]; then
  usage
  exit 1
fi

if [ "$1" == "--provides" ]; then
  echo "portbymac"

if [ "$1" == "portbymac" ]; then # lower case : separated
  if [ "$2" == "00:00:00:00:00:01" ]; then
    echo 1
  elif [ "$2" == "00:00:00:00:00:02" ]; then
    echo 2
  elif [ "$2" == "00:00:00:00:00:03" ]; then
    echo 3
  elif [ "$2" == "00:00:00:00:00:04" -o "$2" == "01:00:00:00:00:04" ]; then
    echo 4
  elif [ "$2" == "00:00:00:00:00:0A" ]; then
    echo 10
  elif [ "$2" == "00:00:00:00:00:0B" ]; then
    echo 11
  elif [ "$2" == "00:00:00:00:00:0C" ]; then
    echo 12
  fi
fi

Inside the “if [ “$1” == “portbymac” ]; ” you can add the logic to extract the MAC addresses and MAP them to ports.