whereyallfrom by Remote BB - A handy ZSH command to look up MAC address vendors on your network — or any list of MACs you throw at it.

whereyallfrom.sh

function whereyallfrom() {
  OUI_FILE="$HOME/oui.txt"

  if [[ ! -f "$OUI_FILE" ]]; then
    echo "Error: $OUI_FILE not found!"
    return 1
  fi

  clean_mac() {
    echo "$1" | tr -d ':-.' | tr '[:lower:]' '[:upper:]'
  }

  lookup_mac() {
    local mac="$1"
    local ip="$2"
    local cleaned=$(clean_mac "$mac")
    local oui=${cleaned:0:6}

    if [[ "$oui" == "FFFFFF" ]]; then
      echo "$ip | $mac | <broadcast>"
      return
    fi

    # Grab vendor line from (base 16) entries
    vendor=$(grep -i "^$oui" "$OUI_FILE" | grep "(base 16)" | awk -F'\t' '{print $2}' | sed 's/^ *//;s/ *$//' | head -n 1)

    if [[ -z "$vendor" ]]; then
      echo "$ip | $mac | No vendor found"
    else
      echo "$ip | $mac | $vendor"
    fi
  }

  # Print header
  printf "%-16s | %-17s | %-30s\n" "IP Address" "MAC Address" "Vendor"
  printf "%-16s-+-%-17s-+-%-30s\n" "----------------" "-----------------" "------------------------------"

  if [ $# -eq 0 ]; then
    # Parse arp -a output: grab IP and MAC pairs
    arp -a | awk '/at/ {print $2, $4}' | sed 's/[()]//g' | while read -r ip mac; do
      lookup_mac "$mac" "$ip"
    done
  else
    for mac in "$@"; do
      lookup_mac "$mac" "-"
    done
  fi
}

whereyallfrom by Remote BB

A handy ZSH command to look up MAC address vendors on your network — or any list of MACs you throw at it.

---

🚀 What it Does

• Scans your local network (arp -a) for devices
• Extracts their IP and MAC addresses
• Uses a local OUI database (oui.txt) to determine vendor
• Displays results in a clean, aligned table with:
  • IP Address
  • MAC Address
  • Vendor Name

---

🛠️ Setup

1. Download the OUI Database

Download the latest vendor list from the IEEE directly:

🔗 https://standards-oui.ieee.org/oui/oui.txt

Save the file as:

mv ~/Downloads/oui.txt ~/

This script expects it to be located at:

$HOME/oui.txt

---

2. Add the function to your ~/.zshrc

Open your shell config:

nano ~/.zshrc

Paste the following function at the bottom:

# whereyallfrom — uses local OUI file to look up vendors
# Download OUI file from: https://standards-oui.ieee.org/oui/oui.txt
# Save it as: $HOME/oui.txt

function whereyallfrom() {
  OUI_FILE="$HOME/oui.txt"

  if [[ ! -f "$OUI_FILE" ]]; then
    echo "Error: $OUI_FILE not found!"
    return 1
  fi

  clean_mac() {
    echo "$1" | tr -d ':-.' | tr '[:lower:]' '[:upper:]'
  }

  lookup_mac() {
    local mac="$1"
    local ip="$2"
    local cleaned=$(clean_mac "$mac")
    local oui=${cleaned:0:6}

    if [[ "$oui" == "FFFFFF" ]]; then
      echo "$ip | $mac | <broadcast>"
      return
    fi

    vendor=$(grep -i "^$oui" "$OUI_FILE" | grep "(base 16)" | awk -F'\t' '{print $2}' | sed 's/^ *//;s/ *$//' | head -n 1)

    if [[ -z "$vendor" ]]; then
      echo "$ip | $mac | No vendor found"
    else
      echo "$ip | $mac | $vendor"
    fi
  }

  printf "%-16s | %-17s | %-30s\n" "IP Address" "MAC Address" "Vendor"
  printf "%-16s-+-%-17s-+-%-30s\n" "----------------" "-----------------" "------------------------------"

  if [ $# -eq 0 ]; then
    arp -a | awk '/at/ {print $2, $4}' | sed 's/[()]//g' | while read -r ip mac; do
      lookup_mac "$mac" "$ip"
    done
  else
    for mac in "$@"; do
      lookup_mac "$mac" "-"
    done
  fi
}

To save and exit Nano:

• Press Control + X
• Press Y to confirm
• Press Enter to save and close

---

3. Reload your shell

source ~/.zshrc

---

🧪 Usage

# Scan your local network and show vendors
whereyallfrom

# Look up specific MAC addresses (any format)
whereyallfrom 00:1A:2B:3C:4D:5E ee-cd-e0-7f-61-9e 001a.2b3c.4d5e

---

✅ Example Output

IP Address       | MAC Address       | Vendor
-----------------+------------------+------------------------------
192.168.1.12     | 60:3e:5f:66:7e:3a | Apple, Inc.
192.168.1.10     | 92:51:2a:36:d2:49 | Samsung Electronics
-                | 00:1A:2B:3C:4D:5E | CISCO SYSTEMS, INC.

---

💡 Notes

• Requires oui.txt to be downloaded from IEEE and placed in $HOME
• Matches MACs based on the first 6 hex digits (OUI)
• Works without internet access

---

Made with ❤️ by Remote BB
For the nosy network nerd in all of us.