resolv_extension.rb

require 'resolv'

class Resolv

  def self.match?( node )
    case node
    when /\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/
      name = getname(node)
      node == getaddress(name)
    else
      ip = getaddress(node)
      node == getname(ip)
    end
  end

end