ruby.rb

require 'net-ldap'

ldap = Net::LDAP.new
ldap.host = "ad-dns.test.com"
ldap.port = 389
ldap.auth 'CN=LDAP Query,OU=User Accounts,DC=TEST,DC=COM', 'Password@123'

user, psw = "vikas.kumar@TEST.COM", "Password@123"
result = ldap.bind_as(
  :base => "OU=User Accounts,DC=TEST,DC=COM",
  :filter => "(mail=#{user})",
  :password => psw
)
if result
  puts "Authenticated #{result.first.dn}"
else
  puts "Authentication FAILED."
end