Ruby script using Net::LDAP (net/ldap) to authenticate a users account name against an ldap server. This is tested against an AD domain. user@example.com is not the user_name our domain expected. Your milage may vary. Credit to a bunch of tutorials for getting this to work (whose tabs I sadly closed). This shoudl enable you with the right creden…

ldap_auth.rb

require 'net/ldap'
require 'io/console'

class LDAPUser

  def connect(user_name, password)
    ldap = Net::LDAP.new(:host => 'example.com', :port => 389)
    ldap.auth("CN=#{user_name},OU=Users,DC=example,DC=com", password)
    
    begin
      answer = ldap.bind
    rescue
      answer =  false
    end
    answer
  end
end

puts 'User Name:'
user_name = STDIN.gets.chomp

puts 'Pass:'
password = STDIN.noecho(&:gets).chomp

user = LDAPUser.new

if user.connect(user_name, password)
  puts 'Login Successful'
else
  puts 'Login Failed'
end