# File lib/dnstraverse/fingerprint.rb, line 105
    def header2fp(header)
      list = [ header.qr, header.opcode, header.aa, header.tc, header.rd,
      header.ra, header.ad, header.cd, header.get_header_rcode, header.qdcount,
      header.ancount, header.nscount, header.arcount ]
      list.map! do | item |
        next '0' if item.instance_of? FalseClass
        next '1' if item.instance_of? TrueClass
        next "NS_NOTIFY_OP" if item == "Notify"
        item
      end
      return list.join(',').upcase
    end