gistfile1.rb

  def self.local_ip_address
    require 'socket'
    # turn off reverse DNS resolution temporarily
    orig, Socket.do_not_reverse_lookup =
      Socket.do_not_reverse_lookup, true

    # does not actually hit network
    UDPSocket.open do |s|
      s.connect '64.233.187.99', 1
      s.addr.last
    end
  ensure
    Socket.do_not_reverse_lookup = orig
  end