use_ipv6?

# File lib/resolv.rb, line 397
    def use_ipv6? # :nodoc:
      begin
        list = Socket.ip_address_list
      rescue NotImplementedError
        return true
      end
      list.any? {|a| a.ipv6? && !a.ipv6_loopback? && !a.ipv6_linklocal? }
    end