Net_DNS_Packet
     The Net_DNS_Packet class provides methods for
     creating a DNS packet suitable for sending to a nameserver.  It also
     provides the methods of parsing a response from a nameserver into a
     Net_DNS_Packet object.
    
     A standard DNS packet is made up of five main pieces:
     
Header
Question Section
Answer Section
Authority Section
Additional Section
    
     Net_DNS defines the DNS packet header as a
     Net_DNS_Header object.
     Net_DNS_Question defines the question section of
     a packet object.  The remaining three sections should be arrays of
     Net_DNS_RR objects.