root@generate-random:~/mac-addresses/ruby$ _

Generate Random MAC Addresses in Ruby

Complete code tutorial with examples and best practices

Ruby

[ Code Example - Quick Summary ]

Language: Ruby

What: Generate random MAC addresses in Ruby using rand and Faker gem. Covers standard format, locally administered addresses, vendor prefixes, and validation for Rails/RSpec testing.

Try it: Use our interactive Mac-addresses generator or integrate this code into your Ruby application.

Generate random MAC addresses in Ruby using rand and Faker gem. Covers standard format, locally administered addresses, vendor prefixes, and validation for Rails/RSpec testing. Looking for other languages? Check our code examples in PHP , JavaScript , Python , Java , C# , C++ and Go or use our interactive web generator.

Ruby Code Example

require "securerandom"

# Generate random MAC address (standard format)
def random_mac_address
  Array.new(6) { rand(0..255) }.map { |octet| "%02X" % octet }.join(":")
end

# Generate locally administered MAC address (bit 1 of first octet set)
def random_local_mac_address
  # First octet: set bit 1 (locally administered), clear bit 0 (unicast)
  first_octet = (rand(0..127) & 0xFE) | 0x02
  octets = [first_octet] + Array.new(5) { rand(0..255) }
  octets.map { |octet| "%02X" % octet }.join(":")
end

# Generate MAC with specific vendor prefix (OUI)
def random_mac_with_vendor(vendor_prefix = "00:1A:2B")
  vendor = vendor_prefix.split(":")
  remaining = Array.new(6 - vendor.length) { "%02X" % rand(0..255) }
  (vendor + remaining).join(":")
end

# Generate MAC with different separator
def random_mac_formatted(separator = ":")
  Array.new(6) { "%02X" % rand(0..255) }.join(separator)
end

# Validate MAC address format
def valid_mac_address?(mac)
  patterns = [
    /^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$/,  # 00:1A:2B:3C:4D:5E
    /^([0-9A-Fa-f]{2}-){5}[0-9A-Fa-f]{2}$/,  # 00-1A-2B-3C-4D-5E
    /^[0-9A-Fa-f]{12}$/,                      # 001A2B3C4D5E
  ]

  patterns.any? { |pattern| mac.match?(pattern) }
end

# Generate multiple MAC addresses
def generate_mac_addresses(count = 10)
  count.times.map { random_mac_address }
end

# Using Faker gem (add to Gemfile: gem 'faker')
# require 'faker'
# mac = Faker::Internet.mac_address
# mac_dash = Faker::Internet.mac_address(prefix: "", separator: "-")

# Usage examples
puts "Random MAC: #{random_mac_address}"
puts "Local MAC: #{random_local_mac_address}"
puts "Vendor MAC: #{random_mac_with_vendor('00:1A:2B')}"
puts "Dash format: #{random_mac_formatted('-')}"
puts "No separator: #{random_mac_formatted('')}"
puts "Is valid: #{valid_mac_address?('00:1A:2B:3C:4D:5E')}"
puts "Batch: #{generate_mac_addresses(3).join(', ')}"

[EXPLANATION]

Ruby's rand(0..255) generates random octets, and "%02X" % octet formats as 2-digit uppercase hexadecimal with zero-padding. Array.new(6) { } creates arrays with block initialization. Locally administered MACs use bitwise operations (& 0xFE and | 0x02). match?() checks regex patterns efficiently. Faker gem provides Internet.mac_address with customizable prefix and separator for realistic test data in Rails, RSpec, and FactoryBot.

Expected Output

Random MAC: A3:45:B7:89:CD:EF
Local MAC: 02:45:B7:89:CD:EF
Vendor MAC: 00:1A:2B:89:CD:EF
Dash format: A3-45-B7-89-CD-EF
No separator: A345B789CDEF
Is valid: true
Batch: 12:34:56:78:9A:BC, DE:F0:12:34:56:78, 9A:BC:DE:F0:12:34